Questions tagged [ibm360]

Questions regarding the IBM System/360 computers and their descendants.

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9 votes
1 answer
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Weird example code for CALL/360:BASIC

The CALL/360:BASIC manual has a couple of simple examples of file I/O. This one has me scratching my head: 10 OPEN 10, 'ITEMFILE', INPUT 20 GET 10: A$,A,B,C,D 30 LET Al = (A+B+C+D)/4 40 PRINT USING ...
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7 votes
1 answer
397 views

Why did IBM skip "System/380" as a mainframe family name?

I've been reading Exhibit 14971 from US vs. IBM (Parts 1, 2, 3) which seems to give a very good overview of the history of the computer industry up to 1980, particularly the way IBM handled its ...
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2 votes
1 answer
142 views

Did the IBM 7030 "Stretch" influence the design of PL/I?

The IBM 7030's fixed-point arithmetic model was unusual: binary numbers could have any number of bits from 1-64. Similarly, PL/I's FIXED BINARY data type has a variable number of bits. On the other ...
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22 votes
3 answers
7k views

What was the rationale behind 32-bit computer architectures?

Though today various power-of-2 word sizes seems to be the norm, back in the 50-60s multiple-of-6 word sizes was more popular and was required by Department of Defense(DOD) in particular. 36-bit ...
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  • 2,438
20 votes
17 answers
4k views

Were any IBM mainframes ever run multiuser?

Now of course there is a sense in which they were – some mainframe installations supported thousands of users! But there is a distinction. Consider the familiar fixture in so many 80s computer science ...
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5 votes
2 answers
375 views

Were there "higher level programming" macro packages for the IBM Macro Assembler?

The IBM/360 Macro Assembly language was quite powerful, allowing non-trivial compile-time string manipulation. Did macro packages exist which would facilitate programming at a (slightly) higher level, ...
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  • 15.8k
2 votes
1 answer
135 views

Any informations on IBM's "Generalized Information System" still available?

I wonder if anyone has documentation left on this topic. In the early 80's, I used to be a 3270 terminal operator, and I wrote programs with GIS. I remember that this language was rather mighty but ...
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13 votes
5 answers
3k views

When did IBM start to use ASCII?

I’m trying to figure out when IBM switched to ASCII and when ASCII became a worldwide standard. Moreover, did IBM make ASCII standard worldwide? What I have found: According to Wikipedia, IBM System /...
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2 votes
3 answers
364 views

Why did IBM System 360 have byte addressable RAM

According to wiki IBM System 360 had byte addressable RAM. Previously IBM had machine with word addressable memory. Did they make a switch for comparability between different machines? Or it was just ...
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5 votes
3 answers
1k views

Why did IBM System /360 have byte addressable RAM, but didn't have 8 bits registers

According to wiki IBM System /360 had only 32 and 64-bits registers for data. I'm wondering if they used 8-bits symbol it means that they stored it in a 32-bits register. Did they have any performance ...
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3 votes
2 answers
895 views

Why did IBM 7030 or IBM 360 use byte and word addressing simultaneously

In 1950s machines had a 36 bit words. And in this word we could pack symbols using 6 bits. And to fetch this symbols from the word programmer should do it using bit manipulations. In 1961 IBM released ...
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6 votes
4 answers
671 views

How was the APL character set represented on IBM mainframes?

The APL language used a unique set of characters, and additionally allowed overstriking of some characters on the terminal to form characters that were used in the language. When an APL workspace was ...
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  • 1,270
2 votes
0 answers
106 views

When and with which system or software was IBM's system of tape headers (VOLx, HDRx, ...) introduced?

Background: IBM compatible tape structure (*1) consists of a series of label blocks describing the volume and each file (Data Set). Essential the structure looks like this: VOL1..9 Volume header ...
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