View source for IBM System/34

{{Short description|IBM midrange computer (1977–1985)}}
{{more citations needed|date=May 2021}}
{{Infobox Computer
| name = IBM System/34
| title = IBM System/34
| aka = S/34
| logo = File:IBM logo.svg
| logo_size = 100px
| image = File:IBM System34 (1) type 5340.jpg
| caption = IBM System/34 type 5340
| manufacturer = International Business Machines Corporation ([[IBM]])
| family = [[System/34]]
| releasedate = {{Start date and age|1977|04}}
| discontinued = February 1985
| os = [[System Support Program]]
| cpu = MSP and CSP
| memory = 48K – 256K
| predecessor = [[IBM System/32]]
| successor = [[IBM System/36]], [[IBM System/38]]
| related = [[IBM 5520]]
| website = {{Cite web|title=IBM Archives: System/34
    | url = https://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html
    | archive-url=
https://web.archive.org/web/20181005060844/https://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html
    | archive-date=2018-10-05 |url-status=dead
}}
| dimensions = 1220x660x1570mm
<ref>{{Cite book|url=https://archive.org/details/bitsavers_ibmsystem3nstallationManualPhysicalPlanningSep77_810249/page/n10/mode/1up|title=ibm :: system34 :: GA21-9242-1 System 34 Installation Manual-Physical Planning Sep77|date=1977-03-13}}</ref>
}}
The '''IBM System/34''' was an [[IBM]] [[midrange computer]] introduced in 1977.<ref name="ibm_archives">{{cite web|last=IBM Corporation|title=System/34|url=http://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html|archive-url=https://web.archive.org/web/20050122174350/http://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html|url-status=dead|archive-date=January 22, 2005|work=IBM Archives|date=23 January 2003 |access-date=December 4, 2012}}</ref> It was withdrawn from marketing in February 1985.<ref name="ibm_archives"/>  It was a multi-user, multi-tasking successor to the single-user [[System/32]]. It included two processors, one based on the System/32 and the second based on the [[System/3]]. Like the System/32 and the System/3, the System/34 was primarily programmed in the [[IBM RPG|RPG II]] language.<ref>{{cite web
|url=http://bitsavers.trailing-edge.com/pdf/ibm/system34/SC21-7667-4_System_34_RPG_II_Reference_Manual_Jan82.pdf
|title=System 34 RPG II Reference Manual}}</ref>

==Hardware==
The 5340 System Unit contained the processing unit, the disk storage and the [[floppy disk|diskette drive]]. It had several access doors on both sides. Inside, were swing-out assemblies where the circuit boards and memory cards were mounted. It weighed {{cvt|700|lb|kg}} and used 220V power.<ref>{{cite news |newspaper=[[The New York Times]]
   |url=https://www.nytimes.com/real-estate/usa/tx/collinsville/homes-for-sale/3533-spring-creek-road/2712-56799761
   |title=3533 Spring Creek Road  |date=March 1, 2019
   |quote=Insulated Shop space, with 220V power.}}</ref> The [[IBM 5250]] series of [[Computer terminals|terminals]] were the primary interface to the System/34.

===Processors===
S/34s had two processors, the Control Storage Processor (CSP), and the Main Storage Processor (MSP). The MSP was the workhorse, based on [[System/3]] architecture; it performed the instructions in the computer programs. The CSP was the governor, a different processor with different [[RISC]]-like instruction set, based on [[System/32]] architecture; it performed system functions in the background. The CSP also executed the optional ''Scientific Macroinstructions'', which were a set of emulated floating point operations used by the System/34 Fortran compiler and optionally in assembly code.<ref>{{cite web|url=http://www.bitsavers.org/pdf/ibm/system34/SA21-9275-0_IBM_System_34_and_System_32_Scientific_Microinstructions_Functions_Reference_Manual_1st_ed_197807.pdf|title=IBM System/34 and IBM System/32 Scientific Macroinstructions Functions Reference Manual|date=July 1978|publisher=IBM|access-date=2021-12-22|website=Bitsavers}}</ref> The clock speed of the CPUs inside a System/34 was fixed at 1&nbsp;MHz for the MSP and 4&nbsp;MHz for the CSP. Special utility programs were able to make direct calls to the CSP to perform certain functions; these are usually system programs like $CNFIG which was used to configure the computer system.
[[File:IBM System34 drives.jpg|left|thumb|Picture of a System/34 showing the diskette magazine drive]]

===Memory and storage===
The smallest S/34 had 48K of RAM and an 8.6 MB hard drive. The largest configured S/34 could support 256K of RAM and 256MB of disk space. S/34 hard drives contained a feature called "the extra cylinder," so that bad spots on the drive were detected and dynamically mapped out to good spots on the extra cylinder. Disk space on the System/34 was organized by [[Block (data storage)|blocks]] of 2560 bytes.

The System/34 supported [[memory paging]], referring to as ''swapping''.<ref>{{cite web|url=http://bitsavers.org/pdf/ibm/system34/SC21-7742-3_System_34_Concepts_and_Design_Guide_Jan82.pdf|title=System/34 Concepts and Design Guide|date=January 1982|access-date=2021-08-01|publisher=IBM}}</ref> The System/34 could either swap out entire programs, or individual segments of a program in order to free up memory for other programs to run.

One of the machine's most distinctive features was an off-line storage mechanism that utilized "{{Visible anchor|magazines}}"—boxes of 8-inch floppies that the machine could [[#Upto23|load and eject]] in a nonsequential fashion.<ref name="S34intro78" /><ref>"the diskette magazine drive can process up to 23 diskettes without manual intervention. -p.11</ref><ref>"three slots for holding individual diskettes and two slots for holding magazines of 10 individual diskettes." -p.20</ref>

{{Clear}}

==Software==
[[File:IBM System34.IsettAcres.jpg|thumb|IBM System/34 with [[IBM 5250|5251 terminal]] (on top) and 5211 printer (right, with top opened)]]
===Operating System===
{{Main|System Support Program}}

The [[System Support Program]] (SSP) was the only operating system of the S/34.  It contained support for multiprogramming, multiple processors, 36 devices, job queues, printer queues, security, [[indexed file]] support. Fully installed, it was about 5 MB.<ref>{{cite web
|title=IBM System/34 System Support Program Logic Manual
|url=http://bitsavers.trailing-edge.com/pdf/ibm/system34/plm/LY21-0050-0_System_34_System_Support_Program_Logic_Manual_System_Dec77.pdf}}</ref> The [[Operational Control Language]] (OCL) was the control language of SSP.

===Programming===
The System/34's initial programming languages were limited to [[RPG II]] and Basic Assembler<ref>{{cite news   
   |newspaper=[[Computerworld]] |date=September 26, 1977 |page=23
   |url=https://www-merlijn.archive.org/details/computerworld1139unse/page/23/mode/1up
   |title=Fortran IV One Highlight Of IBM 34 Enhancements}}</ref> when introduced in 1977.<ref>{{cite news |newspaper=[[The New York Times]]
   |url=https://www.nytimes.com/1983/05/17/business/ibm-introduces-computer-to-replace-system-34-model.html
   |title=I.B.M. introduces computer to replace System 34 model
   |author=Andrew Pollack  |date=May 17, 1983}}</ref> [[FORTRAN]] was fully available six months after the 34's introduction,<ref name=S34intro78>{{cite book  
   |url=http://www.bitsavers.org/pdf/ibm/system34/GC21-5153-2_System_34_Introduction_Mar78.pdf
   |title=System/34 Introduction  |date=March 1978}}</ref> and [[COBOL]] was available as a [[Request price quotation|PRPQ]].<ref>"potentially available ... special order"</ref> [[System/34 BASIC|BASIC]] was introduced later.

==Successor systems==

The [[IBM System/38]] was intended to be the successor of the System/34 and the earlier System/3x systems. However, due to the delays in the development of the System/38 and the high cost of the hardware once complete, IBM developed the simpler and cheaper [[System/36]] platform which was more widely adopted than the System/38.<ref name="inside-as400">{{cite book|title=Inside the AS/400, Second Edition|url=https://books.google.com/books?id=5DoPAAAACAAJ|isbn=978-1882419661|author=Frank G. Soltis|year=1997|publisher=Duke Press}}</ref> The System/36 was an evolution of the System/34 design, but the two machines were not object-code compatible. Instead, the System/36 offered source code compatibility, allowing System/34 applications to be recompiled on a System/36 with little to no changes. Some System/34 hardware was incompatible with the System/36.

A third-party product from ''California Software Products, Inc.'' named BABY/34 allowed System/34 applications to be ported to [[IBM PC compatible]] hardware running [[MS-DOS]].<ref>{{cite magazine
|magazine=[[Computerworld]]
|date=March 18, 1985
|page=50
|url=https://archive.org/details/computerworld1911unse/page/50/mode/1up
|title=BABY/34™ Software enables you to run IBM System/34 RPG II programs on your PCs, XTs and ATs
}}</ref><ref>{{cite magazine
|magazine=[[InfoWorld]]
|date=July 21, 1986
|page=47
|url=https://books.google.com/books?id=Yi8EAAAAMBAJ
|title=Product Briefs}}</ref>

==References==
{{Reflist}}

==Further reading==
*{{cite book|last=Massoglia|first=Charles|title=Everything You Always Wanted to Know About the System/34 But Nobody Told You}} 
*{{cite book|last=Massoglia|first=Charles|title=System/3, System/34, and System/36 Disk Sort as a Programming Language}}

*{{cite book|last=Massoglia|first=Charles|title=Writing and Using System/34 Procedures Effectively}}{{Citation needed|date=October 2023|reason=No trace of references to this title [https://www.linkedin.com/in/charles-massoglia-81aba52   at author's Linkedin profile] or anywhere else online (except for clones of this page).}}
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*{{cite book|last=Lee|first=Merikay|title=Everything You Always Wanted to Know About POP But Nobody Told You}}{{Citation needed|date=October 2023|reason=No trace of references to this title or author found online (except for clones of this page).}}
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==External links==
* {{Cite web|title=IBM Archives: System/34
    | url = https://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html
    | archive-url=
https://web.archive.org/web/20181005060844/https://www-03.ibm.com/ibm/history/exhibits/vintage/vintage_4506VV2236.html
    | archive-date=2018-10-05 |url-status=dead
}}
* {{Cite web
| title=Bitsavers Archive of System/34 Documentation 
| url=http://bitsavers.trailing-edge.com/pdf/ibm/system34/}}

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{{S-other|[[IBM midrange computers]]}}
{{s-bef|before=[[IBM System/3]]}}
{{s-ttl|rows=2|title=IBM System/34|years=1977–1985}}
{{s-aft|rows=2|after=[[IBM System/36]]}}
{{s-bef|before=[[IBM System/32]]}}
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{{IBM midrange computers}}
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{{DEFAULTSORT:Ibm System 34}}
[[Category:IBM minicomputers|System 34]]
[[Category:Computer-related introductions in 1977]]
[[Category:16-bit computers]]