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Sistema / 370
Ordinateurs centraux 348-3-001.jpg
DiseñadorIBM
Bits32 bits
Introducido1970
DiseñoCISC
TipoRegistro-Registro
Registro-Memoria
Memoria-Memoria
CodificaciónVariable (2, 4 o 6 bytes de longitud)
DerivaciónCódigo de condición , indexación, recuento
EndianidadGrande
PredecesorSistema / 360
SucesorS / 370-XA, ESA / 370, ESA / 390 , z / Arquitectura
Registros
Propósito generaldieciséis
Punto flotante4 64 bits
Historia de los mainframes de IBM , desde 1952 hasta el presente
Nombre de mercado
Arquitectura

El IBM System / 370 ( S / 370 ) es una gama de modelos de computadoras centrales IBM anunciadas el 30 de junio de 1970 como sucesoras de la familia System / 360 . La serie principalmente [a] mantiene la compatibilidad con versiones anteriores del S / 360, lo que permite una ruta de migración fácil para los clientes; esto, además de un mejor rendimiento, fueron los temas dominantes del anuncio del producto. En septiembre de 1990, la línea System / 370 fue reemplazada por System / 390 .

Evolución [ editar ]

La línea System / 370 original fue anunciada el 30 de junio de 1970 con el primer envío a clientes de los Modelos 155 y 165 planeado para febrero de 1971 y abril de 1971 respectivamente. [1] El 155 se envió por primera vez en enero de 1971. [2] : El 643 System / 370 experimentó varias mejoras arquitectónicas durante sus aproximadamente 20 años de vida útil. [3] [4] [5] [6] [7] [8] [9]

Las siguientes características mencionadas en Principios de funcionamiento [3] son opcionales en S / 360 pero estándar en S / 370, se introdujeron con S / 370 o se agregaron a S / 370 después del anuncio.

  • Bifurcar y guardar
  • Direccionamiento de datos indirectos de canal
  • Conmutación de canales
  • Borrar E / S
  • Comando Reintentar
  • Conjunto de instrucciones comerciales [b]
  • Intercambio condicional
  • Comparador de reloj y temporizador de CPU
  • Espacio de direcciones dobles (DAS)
  • Extendido
  • Punto flotante de precisión extendida [c]
  • Direccionamiento real extendido
  • Señales externas
  • Liberación rápida
  • Punto flotante [b]
  • Detener dispositivo
  • Cierre de sesión extendido de E / S
  • Cierre de sesión de canal limitado
  • Mover inverso [d]
  • Multiprocesamiento [e]
  • Manejo de llaves PSW
  • Extensiones de recuperación
  • Protección de segmento
  • Señal de servicio
  • Inicio-E / S-Cola rápida
  • Extensiones de instrucción de clave de almacenamiento
  • Bloque de 4 bytes de claves de almacenamiento
  • Suspender y reanudar
  • Bloque de prueba
  • Traducción [f]
  • Vector [g]
  • IDAW de 31 bits

Modelos iniciales [ editar ]

Las primeras máquinas System / 370, el modelo 155 y el modelo 165 , incorporaron solo una pequeña cantidad de cambios en la arquitectura del System / 360. Estos cambios incluyeron: [10]

  • 13 nuevas instrucciones, entre las que se encontraban
  • MOVER LARGO ( MVCL ); [11]
  • COMPARAR LARGO LÓGICO ( CLCL ); [12]
permitiendo así operaciones en hasta 2 ^ 24-1 bytes (16 MB), frente a los límites de 256 bytes en MVC y CLC de 360;
  • SHIFT AND ROUND DECIMAL ( SRP ), [13] , que multiplica o divide un valor decimal empaquetado por una potencia de 10, redondeando el resultado al dividir;
  • aritmética de coma flotante opcional de 128 bits ( hexadecimal ) , introducida en System / 360 Modelo 85 [14] [15]
  • un nuevo reloj con la hora del día de mayor resolución [16]
  • soporte para el canal multiplexor de bloque [17] introducido en el System / 360 Modelo 85. [18]
  • Todas las funciones del emulador fueron diseñadas para ejecutarse bajo el control de los sistemas operativos estándar. IBM documentó los programas emuladores de S / 370 como emuladores integrados.

Estos modelos tenían memoria central y no incluían soporte para almacenamiento virtual .

Tecnología lógica [ editar ]

Todos los modelos del System / 370 utilizaron la forma de IBM de circuitos integrados monolíticos llamados MST (Tecnología de sistema monolítico), lo que los convierte en computadoras de tercera generación. MST proporcionó al System / 370 de cuatro a ocho veces la densidad del circuito y más de diez veces la confiabilidad en comparación con la tecnología SLT de segunda generación anterior del System / 360. [2] : 440

Memoria monolítica [ editar ]

El 23 de septiembre de 1970, IBM anunció el Modelo 145 , un tercer modelo del System / 370, que fue el primer modelo en contar con una memoria principal de semiconductores hecha de circuitos integrados monolíticos y su entrega estaba programada para fines del verano de 1971. Todo lo posterior Los modelos S / 370 utilizaron dicha memoria.

Almacenamiento virtual [ editar ]

En 1972, se realizó un cambio muy significativo cuando se introdujo el soporte para almacenamiento virtual con el anuncio de IBM "System / 370 Advanced Function". IBM había elegido inicialmente (y de manera controvertida) excluir el almacenamiento virtual de la línea S / 370. [2] : 479–484 [19] El anuncio del 2 de agosto de 1972 incluyó:

  • Dirección de hardware de reubicación en todos los S / 370 excepto en los modelos originales 155 y 165
  • los nuevos modelos 158 y 168 S / 370, con hardware de reubicación de direcciones
  • cuatro nuevos sistemas operativos: DOS / VS (DOS con almacenamiento virtual), OS / VS1 ( OS / 360 MFT con almacenamiento virtual), OS / VS2 (OS / 360 MVT con almacenamiento virtual) Versión 1, denominado SVS (Almacenamiento virtual único) y Versión 2, denominada MVS (Almacenamiento virtual múltiple) y se prevé que esté disponible 20 meses después (a finales de marzo de 1974), y VM / 370 : el CP / CMS reimplementado
Sistema / 370-145 Representación 3D
Representación 3D del centro informático con unidades de cinta IBM System / 370-145 e IBM 2401
Sistema / 370-145 Representación 3D
Consola del sistema System / 370-145.

De hecho, el almacenamiento virtual se había entregado en hardware S / 370 antes de este anuncio:

  • En junio de 1971, en el S / 370-145 (uno de los cuales tuvo que ser "contrabandeado" al Centro Científico de Cambridge para evitar que alguien notara la llegada de un S / 370 a ese semillero de desarrollo de memoria virtual, ya que esto habría señalado que el S / 370 estaba a punto de recibir tecnología de reubicación de direcciones). (Varian 1997: p29 [20] ) El S / 370-145 tenía una memoria asociativa [21] [22] utilizada por el microcódigo para la función de compatibilidad con DOS desde sus primeros envíos en junio de 1971; [21]el mismo hardware fue utilizado por el microcódigo para DAT. Aunque IBM eligió excluir el almacenamiento virtual del anuncio de S / 370, esa decisión se reconsideró durante la finalización de la ingeniería 145, en parte debido a la experiencia de memoria virtual en CSC y en otros lugares. La arquitectura de microcódigo 145 simplificó la adición de almacenamiento virtual, lo que permitió que esta capacidad estuviera presente en los primeros 145 sin las extensas modificaciones de hardware necesarias en otros modelos. Sin embargo, IBM no documentó la capacidad de almacenamiento virtual del 145, ni anotó los bits relevantes en los registros de control y PSW que se mostraban en el panel de control del operador cuando se seleccionaban usando los interruptores de rodillo. Sin embargo, los bits de referencia y cambio de las claves de protección de almacenamiento estaban etiquetados en los rodillos,un obsequio para cualquiera que hubiera trabajado con el anterior 360/67. Los clientes actuales de S / 370-145 se alegraron de saber que no tenían que comprar una actualización de hardware para ejecutar DOS / VS o OS / VS1 (o OS / VS2 Release 1, lo cual era posible, pero no común debido a la cantidad limitada de almacenamiento principal disponible en el S / 370-145).

Poco después del anuncio del 2 de agosto de 1972, las actualizaciones de la caja DAT (hardware de reubicación de direcciones) para el S / 370-155 y S / 370-165 se anunciaron silenciosamente, pero solo estaban disponibles para su compra por clientes que ya poseían un Modelo 155 o 165 . [23] Después de la instalación, estos modelos se conocen como la S / 370-155-II y S / 370 a 165-II. IBM quería que los clientes actualizaran sus sistemas 155 y 165 a los ampliamente vendidos S / 370-158 y -168. [24] Estas actualizaciones eran sorprendentemente caras ($ 200 000 y $ 400 000, respectivamente) y tenían plazos de entrega largos después de haber sido ordenadas por un cliente; en consecuencia, nunca fueron populares entre los clientes, la mayoría de los cuales alquilaba sus sistemas a través de una empresa de arrendamiento externa. [23]Esto llevó a que los modelos originales S / 370-155 y S / 370-165 se describieran como "anclas de barco". La actualización, necesaria para ejecutar OS / VS1 o OS / VS2, no fue rentable para la mayoría de los clientes cuando IBM pudo entregarla e instalarla, por lo que muchos clientes se quedaron con estas máquinas ejecutando MVT hasta que finalizó su arrendamiento. No era inusual que fueran otros cuatro, cinco o incluso seis años para los más desafortunados, y resultó ser un factor significativo [25] en la lenta adopción de OS / VS2 MVS, no solo por parte de los clientes en general, pero también para muchos sitios internos de IBM.

Mejoras posteriores [ editar ]

Los cambios arquitectónicos posteriores involucraron principalmente expansiones en la memoria (almacenamiento central), tanto la memoria física como el espacio de direcciones virtuales , para permitir cargas de trabajo más grandes y satisfacer las demandas de los clientes de más almacenamiento. Esta fue la tendencia inevitable cuando la Ley de Moore erosionó el costo unitario de la memoria. Al igual que con todo el desarrollo de mainframe de IBM, preservar la compatibilidad con versiones anteriores era primordial. [ cita requerida ]

  • Asistencia específica del sistema operativo, soporte del programa de control extendido (ECPS). funciones extendidas de instalación y extensión para OS / VS1, MVS [h] y VM. [i] La explotación de los niveles de estos sistemas operativos, por ejemplo, MVS / Extensiones del sistema (MVS / SE), reduce la longitud de la ruta para algunas funciones frecuentes.
  • La función Dual Address Space [26] (DAS) permite que un programa privilegiado mueva datos entre dos espacios de direcciones sin la sobrecarga de asignar un búfer en el almacenamiento común, mover los datos al búfer, programar un SRB en el espacio de direcciones de destino, mover los datos a su destino final y liberando el búfer. IBM ofreció inicialmente DAS solo en el 3033, pero luego lo puso a disposición para unos 4341 [27] y 3031 procesadores. MVS / System Product (MVS / SP) Versión 1 explotó DAS si estaba disponible.
  • En octubre de 1981, los procesadores 3033 y 3081 agregaron "direccionamiento real extendido", que permitía direccionamiento de 26 bits para almacenamiento físico (pero aún imponía un límite de 24 bits para cualquier espacio de direcciones individual). Esta capacidad apareció más tarde en otros sistemas, como el 4381 y el 3090.
  • La Arquitectura Extendida System / 370 (S / 370-XA), disponible por primera vez a principios de 1983 en los procesadores 3081 y 3083, proporcionó una serie de mejoras importantes, que incluyen: expansión del espacio de direcciones de 24 bits a 31 bits ; facilitar el movimiento de datos entre dos espacios de direcciones; y un rediseño completo de la arquitectura de E / S. La capacidad de servicios de memoria cruzada que facilitó el movimiento de datos entre espacios de direcciones estaba disponible justo antes de la arquitectura S / 370-XA en los procesadores 3031, 3032 y 3033.
  • En febrero de 1988, IBM anunció Enterprise Systems Architecture / 370 (ESA / 370) para los modelos mejorados ( E ) 3090 y 4381. Agregó dieciséis registros de acceso de 32 bits , más modos de direccionamiento y varias facilidades para trabajar con múltiples espacios de direcciones simultáneamente.
  • El 5 de septiembre de 1990, IBM anunció Enterprise Systems Architecture / 390 [28] (ESA / 390), compatible con ESA / 370.

Ampliando el espacio de direcciones [ editar ]

Como se describió anteriormente, la línea de productos S / 370 experimentó un cambio arquitectónico importante: la expansión de su espacio de direcciones de 24 a 31 bits.

La evolución del direccionamiento S / 370 siempre fue complicada por el diseño básico del conjunto de instrucciones S / 360 y su gran base de código instalado, que se basaba en una dirección lógica de 24 bits . (En particular, una instrucción de máquina muy utilizada, "Load Address" (LA), borró explícitamente los ocho bits superiores de la dirección que se coloca en un registro. Esto creó enormes problemas de migración para el software existente).

La estrategia elegida fue implementar el direccionamiento ampliado en tres etapas:

  1. primero a nivel físico (para habilitar más hardware de memoria por sistema)
  2. luego en el nivel del sistema operativo (para permitir que el software del sistema acceda a múltiples espacios de direcciones y utilice espacios de direcciones más grandes)
  3. finalmente en el nivel de la aplicación (para permitir que las nuevas aplicaciones accedan a espacios de direcciones más grandes)

Dado que el conjunto de instrucciones del núcleo S / 360 permaneció orientado a un universo de 24 bits, este tercer paso requeriría una ruptura real con el status quo ; Las aplicaciones existentes en lenguaje ensamblador , por supuesto, no se beneficiarían, y se necesitarían nuevos compiladores antes de que se pudieran migrar las aplicaciones que no lo son. Por lo tanto, la mayoría de las tiendas continuaron ejecutando sus aplicaciones de 24 bits en un mundo de 31 bits de mayor rendimiento.

Esta implementación evolutiva (repetida en z / Architecture ) tenía la característica de resolver primero los problemas más urgentes: el alivio del direccionamiento de memoria real era necesario antes que el direccionamiento de memoria virtual. [ cita requerida ]

31 frente a 32 bits [ editar ]

La elección de IBM de direccionamiento de 31 bits (frente a 32 bits) para 370-XA involucró varios factores. El System / 360 Modelo 67 había incluido un modo de direccionamiento completo de 32 bits, pero esta característica no se trasladó a la serie System / 370, que comenzó con solo direccionamiento de 24 bits. Cuando IBM expandió posteriormente el espacio de direcciones S / 370 en S / 370-XA, se citan varias razones para la elección de 31 bits:

  1. El deseo de retener el bit de orden superior como un "bit de control o escape". [29] En particular, la convención de llamada de subrutina estándar marcó la palabra de parámetro final estableciendo su bit alto.
  2. Interaction between 32-bit addresses and two instructions (BXH and BXLE) that treated their arguments as signed numbers (and which was said to be the reason TSS used 31-bit addressing on the Model 67). (Varian 1997:p26, note 85[20])
  3. Input from key initial Model 67 sites, which had debated the alternatives during the initial system design period, and had recommended 31 bits (instead of the 32-bit design that was ultimately chosen at the time). (Varian 1997:pp8–9, note 21,[20] includes other comments about the "Inner Six" Model 67 design disclosees)

Series and models[edit]

Models sorted by date introduced (table)[edit]

The following table summarizes the major S/370 series and models. The second column lists the principal architecture associated with each series. Many models implemented more than one architecture; thus, 308x processors initially shipped as S/370 architecture, but later offered XA; and many processors, such as the 4381, had microcode that allowed customer selection between S/370 or XA (later, ESA) operation.

Tenga en cuenta también el confuso término "compatible con System / 370", que apareció en los documentos fuente de IBM para describir ciertos productos. Fuera de IBM, este término describiría con mayor frecuencia sistemas de Amdahl Corporation , Hitachi Ltd. y otros, que podrían ejecutar el mismo software S / 370. Esta elección de terminología por parte de IBM puede haber sido un intento deliberado de ignorar la existencia de esos fabricantes de conectores compatibles (PCM), porque competían agresivamente contra el dominio del hardware de IBM.

Primer año
de serie		Arquitectura
Nivel de mercado		SerieModelos
1970Sistema / 370 (sin DAT)gama altaSistema / 370-xxx-155, -165, -195
1970Sistema / 370 (DAT)rango medio-145 [30] y -135
1972Sistema / 370gama alta-158 y -168
entrada-115 y -125
rango medio-138 y -148
1977Compatible con sistema / 370 [31]gama alta303x3031, 3032, 3033
1979entrada / mediados43xx4331, 4341, 4361
1980gama alta308x3081, 3083, 3084
1981Sistema / 370-XA
1983rango medio43814381
1986gama alta3090-120 hasta -600
1986Compatible con sistema / 370 [32]entrada937x9370, ...
1988ESA / 370gama altaES / 3090ES / 3090
1988rango medioES / 4381-90, -91, -92

Modelos agrupados por número de modelo (detallado) [ editar ]

IBM utilizó el nombre System / 370 para anunciar las siguientes once ofertas (3 dígitos):

Sistema / 370 Modelo 115 [ editar ]

El IBM System / 370 Modelo 115 se anunció el 13 de marzo de 1973 [33] como "un sistema de entrada System / 370 ideal para los usuarios del sistema informático System / 3 , 1130 de IBM y los modelos System / 360 20 , 22 y 25 ".

Se entregó con "un mínimo de dos (de las recientemente anunciadas por IBM) unidades de disco IBM 3340 conectadas directamente ". [33] Se pueden conectar hasta cuatro 3340.

La CPU se puede configurar con 65,536 (64 K) o 98,304 (96 K) bytes de memoria principal. Un emulador 360/20 opcional estaba disponible.

El 115 fue retirado el 9 de marzo de 1981.

Sistema / 370 Modelo 125 [ editar ]

El IBM System / 370 Modelo 125 se anunció el 4 de octubre de 1972. [34]

Dos, tres o cuatro unidades de almacenamiento en disco IBM 3333 conectadas directamente proporcionaron "hasta 400 millones de bytes en línea".

La memoria principal era de 98.304 (96K) o 131.072 (128K) bytes.

El 125 fue retirado el 9 de marzo de 1981.

Sistema / 370 Modelo 135 [ editar ]

El IBM System / 370 Modelo 135 se anunció el 8 de marzo de 1971. [35] Las opciones para el 370/135 incluían una selección de cuatro tamaños de memoria principales; También se ofreció la emulación de la serie IBM 1400 (1401, 1440 y 1460).

Un "dispositivo de lectura ubicado en la consola del Modelo 135" permitió actualizaciones y agregar funciones al microcódigo del Modelo 135.

El 135 fue retirado el 16 de octubre de 1979.

Sistema / 370 Modelo 138 [ editar ]

El IBM System / 370 Modelo 138 que se anunció el 30 de junio de 1976 se ofreció con 524,288 (512K) o 1,048,576 (1 MB) de memoria. Este último era "el doble de la capacidad máxima del Modelo 135", que "se puede actualizar a los niveles de rendimiento interno de la nueva computadora en las ubicaciones de los clientes". [36]

El 138 fue retirado el 1 de noviembre de 1983.

Sistema / 370 Modelo 145 [ editar ]

Artículo principal: IBM System / 370 Modelo 145

El IBM System / 370 Modelo 145 se anunció el 23 de septiembre de 1970, tres meses después de los modelos 155 y 165. [30] Se envió por primera vez en junio de 1971. [2] : 643

El primer System / 370 en usar memoria principal monolítica, el Modelo 145 se ofreció en seis tamaños de memoria. Una parte de la memoria principal, el "Almacenamiento de control recargable" (RCS) se cargó desde un cartucho de disco preescrito que contiene un microcódigo para implementar, por ejemplo, todas las instrucciones necesarias, canales de E / S e instrucciones opcionales para permitir que el sistema emule antes. Máquinas IBM. [30]

El 145 fue retirado el 16 de octubre de 1979.

Sistema / 370 Modelo 148 [ editar ]

The IBM System/370 Model 148 had the same announcement and withdrawal dates as the Model 138.[37]

As with the option to field-upgrade a 135, a 370/145 could be field-upgraded "at customer locations" to 148-level performance. The upgraded 135 and 145 systems were "designated the Models 135-3 and 145-3."

System/370 Model 155[edit]

Main article: IBM System/370 Model 155

The IBM System/370 Model 155 and the Model 165 were announced Jun 30, 1970, the first of the 370s introduced.[38] Neither had a DAT box; they were limited to running the same non-virtual-memory operating systems available for the System/360. The 155 first shipped in January 1971.[2]:643

The OS/DOS[39] (DOS/360 programs under OS/360), 1401/1440/1460 and 1410/7010[40][41] and 7070/7074 [42] compatibility features were included, and the supporting integrated emulator programs could operate concurrently with standard System/370 workloads.

In August 1972 IBM announced, as a field upgrade only, the IBM System/370 Model 155 II, which added a DAT box.

Both the 155 and the 165 were withdrawn on December 23, 1977.

System/370 Model 158[edit]

The IBM System/370 Model 158 and the 370/168 were announced Aug 2, 1972.[43]

It included dynamic address translation (DAT) hardware, a prerequisite for the new virtual memory operating systems (DOS/VS, OS/VS1, OS/VS2).

A tightly coupled multiprocessor (MP) model was available, as was the ability to loosely couple this system to another 360 or 370 via an optional channel-to-channel adapter.

The 158 and 168 were withdrawn on September 15, 1980.

System/370 Model 165[edit]

Main article: IBM System/370 Model 165

The IBM System/370 Model 165 was described by IBM as "more powerful"[44] compared to the "medium-scale" 370/155. It first shipped in April 1971.[2]:643

Compatibility features included emulation for 7070/7074, 7080, and 709/7090/7094/7094 II.

Some have described the 360/85's use of microcoded vs hardwired as a bridge to the 370/165.[45]

In August 1972 IBM announced, as a field upgrade only, the IBM System/370 Model 165 II which added a DAT box.

The 165 was withdrawn on December 23, 1977.

System/370 Model 168[edit]

Main article: IBM System/370 Model 168

The IBM System/370 Model 168 included "up to eight megabytes"[46] of main memory, double the maximum of 4 megabytes on the 370/158.[43]

It included dynamic address translation (DAT) hardware, a pre-requisite for the new virtual memory operating systems.

Although the 168 served as IBM's "flagship" system,[47] a 1975 newbrief said that IBM boosted the power of the 370/168 again "in the wake of the Amdahl challenge... only 10 months after it introduced the improved 168-3 processor."[48]

The 370/168 was not withdrawn until September 1980.

System/370 Model 195[edit]

The IBM System/370 Model 195 was announced Jun 30, 1970 and, at that time, it was "IBM's most powerful computing system."[49]

Its introduction came about 14 months after the announcement of the 360/195. Both 195 machines were withdrawn Feb. 9, 1977.[50][49]

System/370-compatible[edit]

Beginning in 1977, IBM began to introduce new systems, using the description "A compatible member of the System/370 family."[51][52]

IBM 303X[edit]
Main article: IBM 303X

The first of the initial high end machines, IBM's 3033, was announced March 25, 1977[53] and was delivered the following March, at which time a multiprocessor version of the 3033 was announced.[54] IBM described it[55] as "The Big One."

IBM noted about the 3033, looking back, that "When it was rolled out on March 25, 1977, the 3033 eclipsed the internal operating speed of the company's previous flagship the System/370 Model 168-3 ..."[47]

The IBM 3031 and IBM 3032 were announced Oct. 7, 1977 and withdrawn Feb. 8, 1985.[51][56]

IBM 308X[edit]
Main article: IBM 308X

Three systems comprised the next series of high end machines, IBM's 308X systems:

  • The 3081[57] (announced Nov 12, 1980) had 2 CPUs
  • The 3083[58] (announced Mar 31, 1982) had 1 CPU
  • The 3084[59] (announced Sep 3, 1982) had 4 CPUs

Despite the numbering, the least powerful was the 3083, which could be field-upgraded to a 3081;[58] the 3084 was the top of the line.[59]

These models introduced IBM's Extended Architecture's 31-bit address capability[60] and a set of backward compatible MVS/Extended Architecture (MVS/XA) software replacing previous products and part of OS/VS2 R3.8:

NumberName
565-279Basic Telecommunications Access Method/System Product (BTAM/SP)
5668-978Graphics Access Method/System Product (GAM/SP)
5740-XC6MVS/System Product - JES2 Version 2
5685-291MVS/System Product - JES3 Version 2
5665-293TSO Extensions (TSO/E) for MVS/XA[61]
5665-284MVS/Extended Architecture Data Facility Product (DFP) Version 1[62]

All three 308x systems were withdrawn on August 4, 1987.

IBM 3090[edit]
Main article: IBM 3090

The next series of high-end machines, the IBM 3090, began with models[j] 200 and 400.[63] They were announced Feb. 12, 1985, and were configured with two or four CPUs respectively. IBM subsequently announced models 120, 150, 180, 300, 500 and 600 with lower, intermediate and higher capacities; the first digit of the model number gives the number of central processors.

Starting with the E[64] models, and continuing with the J and S models, IBM offered Enterprise Systems Architecture/370[65] (ESA/370), Processor Resource/System Manager (PR/SM) and a set of backward compatible MVS/Enterprise System Architecture (MVS/ESA) software replacing previous products:

NumberName
5685-279BTAM/SP
5668-978GAM/SP 2.0
5685-001MVS/System Product-JES2 Version 3[66]
5685-002MVS/System Product-JES3 Version 3[66]
5665-293TSO Extensions (TSO/E) for MVS/XA
5685-285TSO/E Version 1 Release 4
5685-025TSO/E Version 2
5665-284MVS/XA Data Facility Product (DFP) Version 1[67]
5665-XA2MVS/XA Data Facility Product (DFP) Version 2.3
5665-XA3MVS/DFP Version 3.1

IBM's offering of an optional vector facility (VF) extension for the 3090 came at a time when Vector processing/Array processing suggested names like Cray and Control Data Corporation (CDC).[68][69]

The 200 and 400 were withdrawn on May 5, 1989.

IBM 4300[edit]
Main article: IBM 4300

The first pair of IBM 4300 processors were Mid/Low end systems announced Jan 30, 1979[70][71] as "compact (and).. compatible with System/370."

The 4331 was subsequently withdrawn on November 18, 1981, and the 4341 on February 11, 1986.

Other models were the 4321,[72] 4361[73] and 4381.[74]

The 4361 has "Programmable Power-Off -- enables the user to turn off the processor under program control";[73] "Unit power off" is (also) part of the 4381 feature list.[74]

IBM offered many Model Groups and models of the 4300 family,[k] ranging from the entry level 4331 to the 4381, described as "one of the most powerful and versatile intermediate system processors ever produced by IBM."[l]

The 4381 Model Group 3 was dual-CPU.

IBM 9370[edit]
Main article: IBM 9370

This low-end system, announced October 7, 1986,[75] was "designed to satisfy the computing requirements of IBM customers who value System/370 affinity" and "small enough and quiet enough to operate in an office environment."

IBM also noted its sensitivity to "entry software prices, substantial reductions in support and training requirements, and modest power consumption and maintenance costs."

Furthermore, it stated its awareness of the needs of small-to-medium size businesses to be able to respond, as "computing requirements grow," adding that "the IBM 9370 system can be easily expanded by adding additional features and racks to accommodate..."

This came at a time when Digital Equipment Corporation (DEC) and its VAX systems were strong competitors in both hardware and software.[76]

Clones[edit]

In the 360 era, a number of manufacturers had already standardized upon the IBM/360 instruction set and, to a degree, 360 architecture. Notable computer makers included Univac with the UNIVAC 9000 series, RCA with the RCA Spectra 70 series, English Electric with the English Electric System 4, and the Soviet ES EVM. These computers were not perfectly compatible, nor (except for the Russian efforts)[77][78] were they intended to be.

That changed in the 1970s with the introduction of the IBM/370 and Gene Amdahl's launch of his own company. About the same time, Japanese giants began eyeing the lucrative mainframe market both at home and abroad. One Japanese consortium focused upon IBM and two others from the BUNCH (Burroughs/Univac/NCR/Control Data/Honeywell) group of IBM's competitors.[citation needed] The latter efforts were abandoned and eventually all Japanese efforts focused on the IBM mainframe lines.

Some of the era's clones included:

  • Amdahl Corporation 470 series
  • ES EVM
  • Fujitsu
  • Hitachi
  • Mitsubishi
  • Siemens
  • Univac

Architecture details[edit]

IBM documentation numbers the bits from high order to low order; the most significant (leftmost) bit is designated as bit number 0.

IBM S/370 registers
General Registers 0-15

Two's complement value
031
Control Registers 0-15

See Principles of Operation[79]
031
Floating Point Registers 0-6[m]

SBiased exponentMantissa
017831

Mantissa (continued)
3263
S/370 Basic Control mode PSW[80]

Chan.
Mask		I
O		E
X		Key0MWPInterruption Code
0124567811121314151631

ILCCCProgram
Mask		Instruction Address
3233343536394063
S/370 BC mode PSW abbreviations
BitsFieldMeaning
0-5Channel Masks for channels 0-5
6IOI/O Mask for channels > 5
7EXExternal Mask
8-11KeyPSW key
12E=0Basic Control mode
13MMachine-check mask
14WWait state
15PProblem state
16-31ICInterruption Code[81]
32-33ILCInstruction-Length Code[82]
34-35CCCondition Code
36-39PM
Program Mask
BitMeaning
36Fixed-point overflow
37Decimal overflow
38Exponent underflow
39Significance
40-63IAInstruction Address
S/370 Extended Control mode PSW[83]

0R000TI
O		E
X		Key1MWPS0CCProgram
Mask		00000000
0124567811121314151617181920232431

00000000Instruction Address
3263
S/370 EC mode PSW abbreviations
BitsFieldMeaning
1RPER Mask
5TDAT mode
6IOI/O Mask; subject to channel mask in CR2
7EXExternal Mask; subject to external subclass mask in CR0
8-11KeyPSW key
12E=1Extended Control mode
13MMachine-check mask
14WWait state
15PProblem state
16SAddress-Space Control
0=primary-space mode
1=Secondary-space mode
18-19CCCondition Code
20-23PM
Program Mask
BitMeaning
20Fixed-point overflow
21Decimal overflow
22Exponent underflow
23Significance
40-63IAInstruction Address
Extended Architecture Extended Control mode PSW[84]

0R000TI
O		E
X		Key1MWPS0CCProgram
Mask		00000000
0124567811121314151617181920232431

AInstruction Address
323363
S/370-XA EC mode PSW abbreviations
BitsFieldMeaning
1RPER Mask
5TDAT mode
6IOI/O Mask; subject to channel mask in CR2
7EXExternal Mask; subject to external subclass mask in CR0
8-11KeyPSW key
12E=1Extended Control mode
13MMachine-check mask
14WWait state
15PProblem state
16SAddress-Space Control
0=primary-space mode
1=Secondary-space mode
18-19CCCondition Code
20-23PM
Program Mask
BitMeaning
20Fixed-point overflow
21Decimal overflow
22Exponent underflow
23Significance
32AAddressing mode
0=24 bit; 1=31 bit
33-63IAInstruction Address
Enterprise Systems Architecture Extended Control mode PSW[85][86]

0R000TI
O		E
X		Key1MWPASCCProgram
Mask		00000000
0124567811121314151617181920232431

AInstruction Address
323363
ESA EC mode PSW abbreviations
BitsFieldMeaning
1RPER Mask
5TDAT mode
6IOI/O Mask; subject to channel mask in CR2
7EXExternal Mask; subject to external subclass mask in CR0
8-11KeyPSW key
12E=1Extended Control mode
13MMachine-check mask
14WWait state
15PProblem state
16-17ASAddress-Space Control
00=primary-space mode
01=Access-register mode
10=Secondary-space mode
11=Home-space mode
18-19CCCondition Code
20-23PM
Program Mask
BitMeaning
20Fixed-point overflow
21Decimal overflow
22Exponent underflow[n]
23Significance[o]
32AAddressing mode
0=24 bit; 1=31 bit
33-63IAInstruction Address

S/370 also refers to a computer system architecture specification,[87] and is a direct and mostly backward compatible evolution of the System/360 architecture[88] from which it retains most aspects. This specification does not make any assumptions on the implementation itself, but rather describes the interfaces and the expected behavior of an implementation. The architecture describes mandatory interfaces that must be available on all implementations and optional interfaces which may or may not be implemented.

Some of the aspects of this architecture are:

  • Big endian byte ordering
  • One or more processors with:
    • 16 32-bit General purpose registers
    • 16 32-bit Control registers
    • 4 64-bit Floating-point registers
    • A 64-bit Program status word (PSW) which describes (among other things)
      • Interrupt masks
      • Privilege states
      • A condition code
      • A 24-bit instruction address
    • Timing facilities (Time of day clock, interval timer, CPU timer and clock comparator)
    • An interruption mechanism, maskable and unmaskable interruption classes and subclasses
    • An instruction set. Each instruction is wholly described and also defines the conditions under which an exception is recognized in the form of program interruption.
  • A memory (called storage) subsystem with:
    • 8 bits per byte
    • A special processor communication area starting at address 0
    • Key controlled protection
    • 24-bit addressing
  • Manual control operations that provide:
    • A bootstrap process (a process called Initial Program Load or IPL)
    • Operator-initiated interrupts
    • Resetting the system
    • Basic debugging facilities
    • Manual display and modifications of the system's state (memory and processor)
  • An Input/Output mechanism – which doesn't describe the devices themselves

Some of the optional features are:

  • A Dynamic Address Translation (DAT) mechanism that can be used to implement a virtual memory system
  • Floating point instructions

IBM took great care to ensure that changes to the architecture would remain compatible for unprivileged (problem state) programs; some new interfaces did not break the initial interface contract for privileged (supervisor mode) programs. Some examples are

ECPS:MVS[89]
A feature to enhance performance for the MVS/370 operating systems
ECPS:VM[90]
A feature to enhance performance for the VM operating systems

Other changes were compatible only for unprivileged programs, although the changes for privileged programs were of limited scope and well defined. Some examples are:

ECPS:VSE[91]
A feature to enhance performance for the DOS/VSE operating system.
S/370-XA[60]
A feature to provide a new I/O interface and to support 31-bit computing

Great care was taken in order to ensure that further modifications to the architecture would remain compatible, at least as far as non-privileged programs were concerned. This philosophy predates the definition of the S/370 architecture and started with the S/360 architecture. If certain rules are adhered to, a program written for this architecture will run with the intended results on the successors of this architecture.


Such an example is that the S/370 architecture specifies that the 64-bit PSW register bit number 32 has to be set to 0 and that doing otherwise leads to an exception. Subsequently, when the S/370-XA architecture was defined, it was stated that this bit would indicate whether the program was a program expecting a 24-bit address architecture or 31-bit address architecture. Thus, most programs that ran on the 24-bit architecture can still run on 31-bit systems; the 64-bit z/Architecture has an additional mode bit for 64-bit addresses, so that those programs, and programs that ran on the 31-bit architecture, can still run on 64-bit systems.

However, not all of the interfaces can remain compatible. Emphasis was put on having non control programs (called problem state programs) remain compatible.[92] Thus, operating systems have to be ported to the new architecture because the control interfaces can (and were) redefined in an incompatible way. For example, the I/O interface was redesigned in S/370-XA making S/370 program issuing I/O operations unusable as-is.

S/370 replacement[edit]

IBM replaced the System/370 line with the System/390 in the 1990s, and similarly extended the architecture from ESA/370 to ESA/390. This was a minor architectural change, and was upwards compatible.

In 2000, the System/390 was replaced with the zSeries (now called IBM System z). The zSeries mainframes introduced the 64-bit z/Architecture, the most significant design improvement since the 31-bit transition.[citation needed] All have retained essential backward compatibility with the original S/360 architecture and instruction set.

GCC and Linux on the S/370[edit]

The GNU Compiler Collection (GCC) had a back end for S/370, but it became obsolete over time and was finally replaced with the S/390 backend. Although the S/370 and S/390 instruction sets are essentially the same (and have been consistent since the introduction of the S/360), GCC operability on older systems has been abandoned.[93] GCC currently works on machines that have the full instruction set of System/390 Generation 5 (G5), the hardware platform for the initial release of Linux/390. However, a separately maintained version of GCC 3.2.3 that works for the S/370 is available, known as GCCMVS.[94]

I/O evolutions[edit]

I/O evolution from original S/360 to S/370[edit]

Main article: IBM System/360 § Channels

The block multiplexer channel, previously available only on the 360/85 and 360/195, was a standard part of the architecture. For compatibility it could operate as a selector channel.[95] Block multiplexer channels were available in single byte (1.5 MB/s) and double byte (3.0 MB/s) versions.

I/O evolution since original S/370[edit]

As part of the DAT announcement, IBM upgraded channels to have Indirect Data Address Lists (IDALs). a form of I/O MMU.

Data streaming channels had a speed of 3.0 MB/s over a single byte interface, later upgraded to 4.5 MB/s.

Channel set switching allowed one processor in a multiprocessor configuration to take over the I/O workload from the other processor if it failed or was taken offline for maintenance.

System/370-XA introduced a channel subsystem that performed I/O queuing previously done by the operating system.

The System/390 introduced the ESCON channel, an optical fiber, half-duplex, serial channel with a maximum distance of 43 kilometers. Originally operating at 10 Mbyte/s, it was subsequently increased to 17 Mbyte/s.

Subsequently, FICON became the standard IBM mainframe channel; FIbre CONnection (FICON) is the IBM proprietary name for the ANSI FC-SB-3 Single-Byte Command Code Sets-3 Mapping Protocol for Fibre Channel (FC) protocol used to map both IBM's antecedent (either ESCON or parallel Bus and Tag) channel-to-control-unit cabling infrastructure and protocol onto standard FC services and infrastructure at data rates up to 16 Gigabits/sec at distances up to 100 km. Fibre Channel Protocol (FCP) allows attaching SCSI devices using the same infrastructure as FICON.

See also[edit]

  • IBM System/360
  • IBM ESA/390
  • IBM System z
  • PC-based IBM-compatible mainframes
  • Hercules emulator

Notes[edit]

  1. ^ E.g., programs that depended on getting program interrupts for alignment errors might fail.
  2. ^ a b Optional on S/360
  3. ^ Previously available on S/360 models 85 and 195
  4. ^ Available as an RPQ on S/360
  5. ^ Previously available on S/360 models 65 and 67 and on the 9020
  6. ^ The Dynamic Address Translation on S/370 is different from that on the 360/67
  7. ^ Only on the 3090
  8. ^ One of these[4] is required for MVS/SE and MVS/SP
    • System/370 extended facility
    • ECPS:MVS
    • 3033 extension feature
  9. ^ VM/370 R2, VM/BSE, VM/SE and VM/SP exploit Virtual-Machine Assist and Shadow-Table-Bypass Assist[5] if they are available.
  10. ^ IBM used a lower case "m"
  11. ^ One announcement alone featured mention of "Twelve models of the 4381" for just 3 "Model Groups" and also listed 6 other Model Groups
  12. ^ The same IBM web page notes the following date announced/withdrawn dates: Model Groups 1 & 2 (Sep 15, 1983 - Feb 11, 1986), Model Group 3 (Oct 25, 1984 - Feb 11, 1986), Model Groups 11, 12, 13 & 14 (announced Feb 11, 1986), Model Groups 21, 22, 23 & 24 (May 19, 1987 - Aug 19, 1992).
  13. ^ The number and format of floating point registers depends on the installed features:
    ESA/370
    ESA/390 without the Advanced Floating Point (AFP) facility
    Only the hexadecimal floating point (HFP) registers FP0, FP2, FP4 and FP6 exist
    ESA/390 with the AFP facility
    FP0-FP15 may be HFP or IEEE floating point
  14. ^ Bit 22 is renamed as HFP exponent underflow in ESA/390
  15. ^ Bit 23 is renamed as HFP significance in ESA/390

References[edit]

S370-1st
IBM System/370 Principles of Operation (PDF) (First ed.). IBM. June 1970. A22-7000-0.
S370
IBM System/370 Principles of Operation (PDF) (Eleventh ed.). IBM. September 1987. A22-7000-10.
S370-MVS
IBM System/370 Assists for MVS (PDF) (Second ed.). IBM. October 1981. GA22-7079-1.
S370-VM
Virtual-Machine Assist and Shadow-Table-Bypass Assist (PDF) (First ed.). IBM. May 1980. GA22-7074-0.
S370-XA-1st
IBM System/370 Extended Architecture Principles of Operation (PDF). IBM. March 1983. SA22-7085-0.
S370-XA
IBM System/370 Extended Architecture Principles of Operation (PDF) (Second ed.). IBM. January 1987. SA22-7085-1.
S370-ESA
IBM Enterprise Systems Architecture/370 Principles of Operation (PDF) (First ed.). IBM. August 1988. SA22-7200-0.
S/390-ESA
IBM Enterprise Systems Architecture/390 Principles of Operation (PDF) (Ninth ed.). IBM. June 2003. SA22-7201-08.
SIE
IBM System/370 Extended Architecture Interpretive Execution (PDF) (First ed.). IBM. January 1984. SA22-7095-0.
  1. ^ "System/370 Announcement". IBM. June 30, 1970.
  2. ^ a b c d e f Pugh, E.W.; L.R. Johnson; John H. Palmer (1991). IBM's 360 and early 370 systems. Cambridge: MIT Press. ISBN 0-262-16123-0.
  3. ^ a b S370, pp. D-1-D-5, Appendix D. Facilities .
  4. ^ a b S370-MVS.
  5. ^ a b S370-VM.
  6. ^ S370-XA, pp. D-1-D-10, Appendix D. Comparison Between System/370 and 370-XA Modes.
  7. ^ SIE.
  8. ^ S370-ESA, pp. D-1-D-5, Appendix D. Comparison Between 370-XA and ESA/370.
  9. ^ S390-ESA, pp. D-1-D-7, Appendix D. Comparison Between ESA/370 and ESA/390.
  10. ^ S370-1st, pp. 2-5, Modifications to System/360.
  11. ^ S370, pp. 7-24 – 7-27, Move Long.
  12. ^ S370, pp. 7-15 – 7-16, Compare Logical Long.
  13. ^ S370, pp. 8-10 – 8-11, Shift and Round Decimal.
  14. ^ "Announcing: System/370 Model 155" (PDF). IBM.
  15. ^ "Announcing System/370 Model 165" (PDF). IBM.
  16. ^ S370, pp. 4-23 – 4-28, Time-Of_Day Clock.
  17. ^ S370, pp. 13-4 – 13-5, Types of Channels.
  18. ^ Richard P. Case; Andris Padegs (January 1978). "Architecture of the IBM System/370" (PDF). Communications of the ACM. 21 (1): 73–96. doi:10.1145/359327.359337. S2CID 207581262. The IBM 2880 Block-Multiplexer Channel included most of the System/370 I/O architecture extensions and was made available on System/360 Models 85 and 195.
  19. ^ "Information technology industry timeline, 1964–1974".
  20. ^ a b c Varian, Melinda Varian (1997). VM and the VM community, past present, and future (PDF). SHARE 89 Sessions 9059-9061.
  21. ^ a b IBM Maintenance Library 3145 Processing Unit Theory - Maintenance (PDF) (Second ed.). IBM. October 1971. pp. CPU 117–129. SY24-3581-1.
  22. ^ IBM Maintenance Library 3145 Processing Unit Theory - Maintenance (Third ed.). IBM. pp. CPU 117–129. SY24-3581-2.
  23. ^ a b "IBM's Virtual Memory 370s," Datamation, September 1972, p.58-61
  24. ^ A. Padegs (September 1981). "System/360 and Beyond". IBM Journal of Research & Development. IBM. 25 (5): 377–390. doi:10.1147/rd.255.0377. – tables include model characteristics (Table 1) and announcement/shipment dates (Table 2). The S/370-155-II and -165-II are listed under the former but not the latter, because the upgraded systems were not formally announced as separate models. The "System/370 Advanced Function" announcement, including the -158 and -168, was the main public event.
  25. ^ "155, 165 Owners Angry with IBM," Datamation, August 1973, p.76-86
  26. ^ Dan Greiner (12 March 2012). Dual Address Space & Linkage-Stack Architecture. SHARE 118 Atlanta. Session 10446.
  27. ^ "Section 80: Comparison Table of Hardware - 4341 Model Group 12 and 4381 Processors" (PDF). A Guide to the IBM 4381 Processor (PDF) (Third ed.). IBM. April 1986. p. 128. GC20·2021·2.
  28. ^ "System/390 Announcement". IBM Archives. IBM. Retrieved 2017-01-29.
  29. ^ A. Padegs (May 1983). "System/370 Extended Architecture: design considerations". IBM Journal of Research & Development. IBM. 27 (3): 198–205. doi:10.1147/rd.273.0198. – a subsection titled "31-bit addressing" begins on page 201.
  30. ^ a b c "System/370 Model 145". IBM Archives. IBM.
  31. ^ "IBM timeline of S/370 series". with surprising term 'System/370-compatible' for the 3xxx and 4xxx series
  32. ^ "IBM 9370 announcement letter". to explain why the 9370 is categorized as a System/370 compatible system
  33. ^ a b "System/370 Model 115". IBM Archives. IBM.
  34. ^ "System/370 Model 125". IBM Archives. IBM.
  35. ^ "System/370 Model 135". IBM Archives. IBM.
  36. ^ "System/370 Model 138". IBM Archives. IBM.
  37. ^ "System/370 Model 148". IBM Archives. IBM.
  38. ^ "System/370 Model 155". IBM Archives. IBM.
  39. ^ IBM System/360 Operating System: DOS Emulator Planning Guide. IBM. GC24-5076.
  40. ^ Emulating the IBM 1401, 1440 and 1460 on the IBM System/370 Models 145 and 155 using OS/360 Program Number 360C-EU-735 (Second ed.), IBM, February 1971, GC27-6945-1
  41. ^ Emulating the IBM 1410 and 7010 on the IBM System/370 Models 145 and 155 using OS/360 Program Number 360C-EU-736 (Second ed.), IBM, June 1971, GC27-6946-1
  42. ^ Emulating the IBM 7074 on the IBM System/370 Models 155 and 165 using OS/360 Program Number 360C-EU-739 (Second ed.). IBM. February 1971. GC27-6948-1.
  43. ^ a b "System/370 Model 158". IBM Archives. IBM.
  44. ^ "System/370 Model 165". IBM Archives. IBM.
  45. ^ Jon Elson (December 5, 2014). "IBM 360/85 vs. 370/165". Newsgroup: alt.folklore.computers.
  46. ^ "System/370 Model 168". IBM Archives. IBM.
  47. ^ a b "IBM's 3033 "The Big One": IBM's 3033". IBM Archives. IBM.
  48. ^ "IBM boosts power of 370/168 again". Computer Weekly (486). 1975. p. 1.
  49. ^ a b "System/370 Model 195". IBM Archives. IBM.
  50. ^ "System/360 Model 195". IBM Archives. IBM.
  51. ^ a b "3031 Processor Complex". IBM Archives. IBM.
  52. ^ "Mainframes - Basic information sources". IBM Archives. IBM.
  53. ^ "3033 Press announcement". IBM Archives. IBM.
  54. ^ "3033 Multiprocessor - Press announcement". IBM Archives. IBM.
  55. ^ "IBM's 3033 "The Big One": IBM's 3033". IBM Archives. IBM. THINK magazine later simply dubbed it – "The Big One."
  56. ^ "3032 Processor Complex". IBM Archives. IBM.
  57. ^ "3081 Processor Complex". IBM Archives. IBM.
  58. ^ a b "3083 Processor Complex". IBM Archives. IBM.
  59. ^ a b "3084 Processor Complex". IBM Archives. IBM.
  60. ^ a b S370-XA-1st.
  61. ^ "TSO Extensions (TSO/E), which enhances and extends the capability of TSO, is announced", Announcement Letters, IBM, November 2, 1981, ZP81-0796
  62. ^ MVS/Extended Architecture Data Facility Product: General Information (PDF) (Third ed.). IBM. January 1984.
  63. ^ "3090 Processor Complex". IBM Archives. IBM.
  64. ^ "IBM 3090 PROCESSOR UNIT MODEL 120E, IBM 3092 PROCESSOR CONTROLLER MODEL 3". IBM. May 19, 1987.
  65. ^ S370-ESA.
  66. ^ a b 5685-001 MVS/System Product-JES2 Version 3 Release 1.0. IBM Sales Manual. IBM.
  67. ^ MVS/Extended Architecture Data Facility Product: General Information (PDF) (Third ed.). IBM. January 1984.
  68. ^ the hyperlink on the words "Vector processing" point to an article that has only 2 mentions of IBM, one of which begins "In 2000, IBM, Toshiba and Sony collaborated."
  69. ^ The "first to market" advantage can be summarized as "In 1972, computer designer Seymour Cray left CDC and formed a new company" as noted in Getting Up to Speed: The Future of Supercomputing, 2005, ISBN 0309165512, by National Research Council, Division on Engineering and Physical Sciences, Computer Science and Telecommunications Board
  70. ^ "4331 Processor". IBM Archives. IBM.
  71. ^ "4341 Processor". IBM Archives. IBM.
  72. ^ https://www.ibm.com/ibm/history/exhibits/dpd50/dpd50_chronology5.html
  73. ^ a b "4361 Processor". IBM Archives. IBM.
  74. ^ a b "4381 Processor". IBM Archives. IBM.
  75. ^ "IBM 9370 INFORMATION SYSTEM OVERVIEW". IBM. October 7, 1986.
  76. ^ "Report Of The SSC Computer Planning Committee" (PDF). January 1990. chapter 5.4, "SUMMARY OF RELATIVE STRENGTH OF DEC/VMS AND IBM/VM".
  77. ^ David S. Bennahum (November 1997). "Heart of Darkness". from 1967 to 1972, it put in place a massive industrial complex to reverse-engineer, copy, and produce IBM mainframes and DEC minicomputers... Once a computer was reduced to its constituent bits on both a software and hardware level, industrial management designed a manufacturing process to replicate the machine... a clone of the IBM 360/40 in 1970, a Cold War coup. Later, he worked on duplicating the IBM 370
  78. ^ Re the 370 (followup to 360/40 clone): Michael Weisskopf (September 24, 1985). "Soviet Radar Allegedly Stolen From U.S." The Washington Post.
  79. ^ S370, pp. 4-10-4-11, Assignment of Control-Register Fields.
  80. ^ S370, pp. 4-8 – 4-9, Program-Status Word Format in BC Mode.
  81. ^ S370, pp. 6-3 – 6-5, Interruption Action.
  82. ^ S370, pp. 6-7 – 6-9, Instruction-Length Code.
  83. ^ S370, pp. 4-6 – 4-7, Program-Status Word Format in EC Mode.
  84. ^ S370-XA, p. 4-5, Program-Status-Word Format.
  85. ^ S370-ESA, p. 4-5, Program-Status-Word Format.
  86. ^ S390-ESA, p. 4-5, Program-Status-Word Format.
  87. ^ S370.
  88. ^ S370, pp. 1-1 – 1-4, Chapter 1 Introduction.
  89. ^ IBM System/370 Extended Facility and ECPS:MVS (Second ed.). IBM. November 1980. GA22-7072-1.
  90. ^ Virtual-Machine Assist and Shadow-Table-Bypass Assist (PDF) (First ed.). IBM. May 1980. GA22-7074-0.
  91. ^ IBM 4300 Processors Principles of Operation for ECPS:VSE Mode (PDF) (Second ed.). IBM. September 1980. GA22-7070-1.
  92. ^ S390-ESA, pp. 1-13 – 1-14, Section 1.3.2.2 Problem-State Compatibility.
  93. ^ "Removed architectures and systems removed from GCC 3.4".
  94. ^ "GCCMVS (GCC 3.2.3 for S/370)".
  95. ^ S370, p. 13-5, Programming Note.

Further reading[edit]

  • Prasad, N.S. (1989). IBM Mainframes. McGraw-Hill. ISBN 0070506868. — Chapter 4 (pp. 111–166) describes the System/370 architecture; Chapter 5 (pp. 167–206) describes the System/370 Extended Architecture.

External links[edit]

  • Hercules System/370 Emulator A software implementation of IBM System/370