IBM System/360 Model 30: Difference between revisions

Revision as of 03:21, 9 October 2023

Revision as of 13:40, 1 January 2024

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==Models==

[[File:IBM System 360 model 30 profile.agr.jpg|thumb|closeup (profile) of 360/30 Console]]

Four models<ref group='NB'>Lower case "M"</ref> of the 360/30 were initially offered.<ref name="mod30-func-char">{{cite book|url=http://www.bitsavers.org/pdf/ibm/360/functional_characteristics/GA24-3231-7_360-30_funcChar.pdf|title=IBM System/360 Model 30 Functional Characteristics|id=GA24-3231-7|date=August 1971}}</ref> They vary by the amount of [[Magnetic-core memory|core memory]] with which the system was offered. The C30, D30, E30 and F30 were respectively configured with 8K, 16K, 32K and 64K of core memory.<ref name="mod30-func-char"/>{{rp|Fig.5, p.9}}

It was little publicized that there were two versions of the Model 30,<ref name="mod30-func-char"/>{{rp|pp.2,8,9}} known (on the rare occasions when they were distinguished at all) as the 30-1 and the 30-2. The original 30-1 had a 2.0 microsecond storage cycle. Later, after the first 1000 30-1 were shipped,<ref name= ibmbook/> it was replaced by the 1.5-microsecond 30-2, although the 30-1 was silently retained in the sales catalog. The two were cosmetically different; the 30-1 looked like other System/360 models, with indicator lamps exposed on the front panel and labeled, but the 30-2 took a retrograde design step, putting the lights behind a stencil, as they had been on pre-360 machines like the [[IBM 1401]].

The (faster) 30-2 had an additional model, DC30, with 24K of memory.<ref name="mod30-func-char"/>{{rp|Fig.4, p.9}}

The 7th edition of IBM System/360 Basic Operating System Programmer's Guide, dated September 1967, lists first among ''major changes'' support for "an intermediate storage size (24K) for System/360 Model 30."<ref name="BOS_ProGuide">{{cite book|url=http://bitsavers.trailing-edge.com/pdf/ibm/360/bos_bps/C24-3372-6_BOSpgmr_Sep67.pdf|title=IBM System/360 Basic Operating System Programmer's Guide|id=C24-3372-6|date=September 1967|publisher=IBM}}</ref>

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The minimum memory needed to run DOS or TOS was 16&nbsp;KB.

TOS [[TOS/360|(Tape Operating System)]], as the name suggests, required a tape drive but no disk. It shared most of the code base<ref name=40Y.mem>{{cite newsgroup|url=https://groups.google.com/d/msg/alt.folklore.computers/RZA6FD27Tc0/-LoIXsOee7gJ|title=DOS/360: Forty years|author=Joe Morris|newsgroup=alt.folklore.computer|date=April 25, 2005|quote=Don't forget TOS, the bastard cousin of DOS. Either could be generated from the same set of distribution libraries...}}</ref> and some manuals<ref>{{cite web|url=http://www.bitsavers.org/pdf/ibm/360/dos/GC24-5030-8_Disk_and_Tape_Operating_Systems_Concepts_and_Facilities_Oct70.pdf|title=IBM System/360 Disk and Tape Operating Systems Concepts and Facilities|date=October 1970|id=GC2ij-5030-8}}</ref><ref>{{cite web|url=http://www.bitsavers.org/pdf/ibm/360/dos/GC24-3465-8_DOS_and_TOS_Utility_Programs_R26.1_Aug73.pdf|title=DOS and TOS Utility Programs|date=August 1973|id=GC24-3465-8}}</ref> with IBM's DOS/360 and went through 14 releases. TOS was discontinued<ref>{{cite mailing list|url=https://www.mail-archive.com/[e-mail]/msg24371.html|author=Anne and Lynn Wheeler|title=Re: IBM 1401|date=May 28, 2009|mailing-list=[e-mail]}}</ref>{{failed verification|date=January 2020}} when disk drives became more affordable.<ref>Computerworld, Sept. 5, 1977, p.40 - quotes an IBM task force report that referred to "price alone rather than by price/performance."</ref>

DOS [[DOS/360|(Disk Operating System)]] was a popular choice for the 360/30.<ref>Of those 360/30 and 360/40 machines still around in 1981/being replaced by 4300 systems, a Computerworld survey showed that DOS was what they ran/had run, May 25, 1981, p. 26</ref><ref>{{cite web|url=http://www.edwardbosworth.com/My3121Textbook_HTM/MyText3121_Ch03_V01.htm|title=Programming Assembler Language on the IBM Mainframes: An Introduction|at=Chapter 3 – The Heritage of the IBM System/360|author=Edward L. Bosworth}}</ref><ref>{{cite web|url=http://ed-thelen.org/comp-hist/ibm-360-30.html|title=IBM System 360, Model 30|author=Ed Thelen}}</ref><ref>{{cite web|url=http://www.highersystems.co.uk/ibm_360_30.html|title=IBM 360/30}}</ref>