Re: ARM is sort of channeling the IBM 360

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Sujet : Re: ARM is sort of channeling the IBM 360
De : SFuld (at) *nospam* alumni.cmu.edu.invalid (Stephen Fuld)
Groupes : comp.arch
Date : 24. Jun 2024, 18:09:24
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Organisation : A noiseless patient Spider
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References : 1 2 3 4
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Lawrence D'Oliveiro wrote:

On Thu, 20 Jun 2024 14:28:04 -1000, Lynn Wheeler wrote:
 
a little over decade ago was asked to track down decision to add
virtual memory to all 370s. basically MVT storage management was so
bad that required specifying region storage requirements four times
larger than used ...
 
Let me see if I got this straight.


You're close.


 
In the early days, the offshoots of OS/360 were “MFT” (“Multiple
Fixed Tasks”)


"Multiprogramming with a Fixed number of Tasks"


and “MVT” (“Multiple Variable Tasks”).


"Multiprogramming with a Variable number of Tasks"



The “Multiple”
part had to do with this new-fangled thing called “multiprogramming”:
basically, there was so much RAM available by that point that you
could typically keep multiple programs memory-resident at once, even
if only one was executing, instead of having to swap everybody but
the current program out.


Right.  So you could make productive use of the CPU while one program
was idle, typically waiting for an I/O.



The difference was, with MFT, a program had to declare its memory
requirement before it could be started, and the only way to change
that was to stop the program and start it again. Whereas MVT allowed
a program to change its memory requirements while it was executing.
(Whoah! Program relocation requirement styleee!)


Not quite.  With MFT, the system operator defined the numbeer and size
of each region of memory.  For example, a site may have two partitions
of 3MB and one of 6MB.  These were rarely changed.  It was the
operator's responsibility to try to maximize system usage by starting
jobs in the appropriate sized partitions.  With MVT, there were no
fixed sized partitions.  The memory requirements for each job were
specified by the job and again, it was the operator's responsibility to
try to maximize usage.

While a job could change its memory requirements with each task,IIRC it
was better to specify the largest requirement in the beginning, and
releasing memory as the largest remaining requirement got smaller.
This was because if the memory requirement increased inn the middle of
the job, you were not quaranteed that the additional memory was
available, and if it wasn't, the job would have to be terminated or
"rolled out" until the required memory was available.  Note, as John
explained, since programs were not relocatable, if a program was rolled
out, it could only be rolled in to the same address it was rolled out
from.



 
Then, when virtual memory came along, MFT became OS/VS1, while MVT
became OS/VS2.
 
Eventually, the MFT→OS/VS1 line died a long-overdue death, and OS/VS2
became “MVS”. Not sure what other name changes happened along the
way, but nowadays this is known as “z/OS”.


Right.

 
Does that make sense?

Close.



--
 - Stephen Fuld
(e-mail address disguised to prevent spam)

Date Sujet#  Auteur
20 Jun 24 * ARM is channeling the IBM 360102John Savard
20 Jun 24 +* Re: ARM is sort of channeling the IBM 36095John Levine
21 Jun 24 i`* Re: ARM is sort of channeling the IBM 36094Lynn Wheeler
24 Jun 24 i `* Re: ARM is sort of channeling the IBM 36093Lawrence D'Oliveiro
24 Jun 24 i  +* Re: ancient OS history, ARM is sort of channeling the IBM 36090John Levine
24 Jun 24 i  i+* Re: ancient OS history, ARM is sort of channeling the IBM 36087Lynn Wheeler
24 Jun 24 i  ii+* Re: ancient OS history, ARM is sort of channeling the IBM 36082Lawrence D'Oliveiro
25 Jun 24 i  iii`* Re: ancient OS history, ARM is sort of channeling the IBM 36081John Levine
25 Jun 24 i  iii +* Re: ancient OS history, ARM is sort of channeling the IBM 36073Lawrence D'Oliveiro
25 Jun 24 i  iii i`* Re: ancient OS history, ARM is sort of channeling the IBM 36072Stephen Fuld
25 Jun 24 i  iii i +* Re: ancient OS history, ARM is sort of channeling the IBM 36064Stephen Fuld
26 Jun 24 i  iii i i`* Re: ancient OS history, ARM is sort of channeling the IBM 36063Stephen Fuld
26 Jun 24 i  iii i i `* Re: ancient OS history, ARM is sort of channeling the IBM 36062Lawrence D'Oliveiro
26 Jun 24 i  iii i i  +* Re: ancient OS history, ARM is sort of channeling the IBM 36057John Levine
26 Jun 24 i  iii i i  i`* Re: ancient OS history, ARM is sort of channeling the IBM 36056Lawrence D'Oliveiro
27 Jun 24 i  iii i i  i `* Re: ancient OS history, ARM is sort of channeling the IBM 36055John Levine
27 Jun 24 i  iii i i  i  `* Re: ancient OS history, ARM is sort of channeling the IBM 36054MitchAlsup1
28 Jun 24 i  iii i i  i   `* Re: ancient OS history, ARM is sort of channeling the IBM 36053Lawrence D'Oliveiro
28 Jun 24 i  iii i i  i    +- Re: TSS I/O, ancient OS history1John Levine
28 Jun 24 i  iii i i  i    `* Re: ancient OS history, ARM is sort of channeling the IBM 36051MitchAlsup1
28 Jun 24 i  iii i i  i     `* Re: ancient OS history, ARM is sort of channeling the IBM 36050Lawrence D'Oliveiro
29 Jun 24 i  iii i i  i      `* Re: ancient OS history, ARM is sort of channeling the IBM 36049Stephen Fuld
29 Jun 24 i  iii i i  i       `* Re: ancient OS history, ARM is sort of channeling the IBM 36048John Levine
30 Jun 24 i  iii i i  i        +* Re: ancient OS history, ARM is sort of channeling the IBM 36032Lawrence D'Oliveiro
30 Jun 24 i  iii i i  i        i+- Re: ancient OS history, ARM is sort of channeling the IBM 3601MitchAlsup1
30 Jun 24 i  iii i i  i        i`* Re: ancient OS history, ARM is sort of channeling the IBM 36030Stephen Fuld
30 Jun 24 i  iii i i  i        i +* Re: ancient OS history, ARM is sort of channeling the IBM 36024Lawrence D'Oliveiro
30 Jun 24 i  iii i i  i        i i+* Re: ancient OS history, ARM is sort of channeling the IBM 36022Lynn Wheeler
30 Jun 24 i  iii i i  i        i ii`* Re: ancient OS history, ARM is sort of channeling the IBM 36021John Dallman
30 Jun 24 i  iii i i  i        i ii +* Re: ancient OS history, ARM is sort of channeling the IBM 36019Thomas Koenig
30 Jun 24 i  iii i i  i        i ii i+* Re: ancient OS history, ARM is sort of channeling the IBM 3608Michael S
30 Jun 24 i  iii i i  i        i ii ii+* Re: ancient OS history, ARM is sort of channeling the IBM 3606Thomas Koenig
30 Jun 24 i  iii i i  i        i ii iii+* Re: ancient OS history, ARM is sort of channeling the IBM 3604Stephen Fuld
30 Jun 24 i  iii i i  i        i ii iiii`* Re: base registers, ancient OS history, ARM is sort of channeling the IBM 3603John Levine
1 Jul 24 i  iii i i  i        i ii iiii `* Re: base registers, ancient OS history, ARM is sort of channeling the IBM 3602Lawrence D'Oliveiro
1 Jul 24 i  iii i i  i        i ii iiii  `- Re: base registers, ancient OS history, ARM is sort of channeling the IBM 3601John Levine
30 Jun 24 i  iii i i  i        i ii iii`- Re: ancient OS history, ARM is sort of channeling the IBM 3601MitchAlsup1
30 Jun 24 i  iii i i  i        i ii ii`- Re: ancient OS history, ARM is sort of channeling the IBM 3601MitchAlsup1
30 Jun 24 i  iii i i  i        i ii i`* Re: ancient OS history, ARM is sort of channeling the IBM 36010John Dallman
30 Jun 24 i  iii i i  i        i ii i +- Re: ancient OS history, ARM is sort of channeling the IBM 3601MitchAlsup1
30 Jun 24 i  iii i i  i        i ii i `* Re: ancient OS history, ARM is sort of channeling the IBM 3608Stephen Fuld
30 Jun 24 i  iii i i  i        i ii i  +- Re: small old machines, ancient OS history, ARM is sort of channeling the IBM 3601John Levine
30 Jun 24 i  iii i i  i        i ii i  +* Re: ancient OS history, ARM is sort of channeling the IBM 3604John Dallman
30 Jun 24 i  iii i i  i        i ii i  i+* Re: ancient OS history, ARM is sort of channeling the IBM 3602Stephen Fuld
30 Jun 24 i  iii i i  i        i ii i  ii`- Re: ancient OS history, ARM is sort of channeling the IBM 3601John Dallman
30 Jun 24 i  iii i i  i        i ii i  i`- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lynn Wheeler
30 Jun 24 i  iii i i  i        i ii i  `* Re: ancient OS history, ARM is sort of channeling the IBM 3602MitchAlsup1
1 Jul 24 i  iii i i  i        i ii i   `- Re: ancient OS history, ARM is sort of channeling the IBM 3601moi
30 Jun 24 i  iii i i  i        i ii `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lynn Wheeler
30 Jun 24 i  iii i i  i        i i`- Re: ancient OS history, ARM is sort of channeling the IBM 3601Stephen Fuld
1 Jul 24 i  iii i i  i        i `* Re: ancient OS history, ARM is sort of channeling the IBM 3605Lawrence D'Oliveiro
2 Jul 24 i  iii i i  i        i  `* Re: ancient OS history, ARM is sort of channeling the IBM 3604John Levine
2 Jul 24 i  iii i i  i        i   `* Re: ancient OS history, ARM is sort of channeling the IBM 3603Lawrence D'Oliveiro
2 Jul 24 i  iii i i  i        i    `* Re: ancient OS history, ARM is sort of channeling the IBM 3602John Levine
2 Jul 24 i  iii i i  i        i     `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Dan Cross
30 Jun 24 i  iii i i  i        `* Re: ancient OS history, ARM is sort of channeling the IBM 36015Anton Ertl
30 Jun 24 i  iii i i  i         `* Re: ancient OS history, ARM is sort of channeling the IBM 36014Anton Ertl
30 Jun 24 i  iii i i  i          `* Re: streams and file locks, ancient OS history, ARM is sort of channeling the IBM 36013John Levine
1 Jul 24 i  iii i i  i           +* Re: streams and file locks, ancient OS history, ARM is sort of channeling the IBM 36010MitchAlsup1
1 Jul 24 i  iii i i  i           i`* Re: streams and file locks, ancient OS history, ARM is sort of channeling9John Levine
1 Jul 24 i  iii i i  i           i `* Re: streams and file locks, ancient OS history, ARM is sort of channeling8MitchAlsup1
1 Jul 24 i  iii i i  i           i  `* Re: streams and file locks, ancient OS history, ARM is sort of channeling7John Levine
1 Jul 24 i  iii i i  i           i   +* Re: streams and file locks, ancient OS history, ARM is sort of channeling2Lawrence D'Oliveiro
1 Jul 24 i  iii i i  i           i   i`- Re: streams and file locks, ancient OS history, ARM is sort of channeling1John Levine
1 Jul 24 i  iii i i  i           i   `* Re: streams and file locks, ancient OS history, ARM is sort of channeling4Michael S
1 Jul 24 i  iii i i  i           i    `* Re: streams and file locks, ancient OS history, ARM is sort of channeling3MitchAlsup1
2 Jul 24 i  iii i i  i           i     +- Re: streams and file locks, ancient OS history, ARM is sort of channeling1Michael S
2 Jul 24 i  iii i i  i           i     `- Re: streams and file locks, ancient OS history, ARM is sort of channeling1Michael S
1 Jul 24 i  iii i i  i           `* Re: streams and file locks, ancient OS history, ARM is sort of channeling the IBM 3602Lawrence D'Oliveiro
1 Jul 24 i  iii i i  i            `- Re: streams and file locks, ancient OS history1John Levine
26 Jun 24 i  iii i i  `* Re: ancient OS history, ARM is sort of channeling the IBM 3604Stephen Fuld
26 Jun 24 i  iii i i   +* Re: ancient OS history, ARM is sort of channeling the IBM 3602John Levine
26 Jun 24 i  iii i i   i`- Re: ancient OS history, ARM is sort of channeling the IBM 3601Stephen Fuld
27 Jun 24 i  iii i i   `- Re: ancient OS history, ARM is sort of channeling the IBM 3601MitchAlsup1
26 Jun 24 i  iii i `* Re: ancient OS history, ARM is sort of channeling the IBM 3607John Levine
26 Jun 24 i  iii i  `* Re: ancient OS history, ARM is sort of channeling the IBM 3606John Levine
27 Jun 24 i  iii i   `* Re: ancient OS history, ARM is sort of channeling the IBM 3605Thomas Koenig
27 Jun 24 i  iii i    `* Re: ancient OS history, ARM is sort of channeling the IBM 3604John Levine
27 Jun 24 i  iii i     +- Re: ancient OS history, ARM is sort of channeling the IBM 3601Thomas Koenig
28 Jun 24 i  iii i     +- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lawrence D'Oliveiro
28 Jun 24 i  iii i     `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lawrence D'Oliveiro
25 Jun 24 i  iii +* Re: ancient OS history, ARM is sort of channeling the IBM 3606Terje Mathisen
25 Jun 24 i  iii i+* Re: ancient OS history, ARM is sort of channeling the IBM 3602Lawrence D'Oliveiro
25 Jun 24 i  iii ii`- Re: ancient OS history, ARM is sort of channeling the IBM 3601Terje Mathisen
25 Jun 24 i  iii i`* Re: ancient OS history, ARM is sort of channeling the IBM 3603Michael S
26 Jun 24 i  iii i `* Re: ancient OS history, ARM is sort of channeling the IBM 3602Michael S
26 Jun 24 i  iii i  `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Terje Mathisen
25 Jun 24 i  iii `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lynn Wheeler
24 Jun 24 i  ii`* Re: ancient OS history, ARM is sort of channeling the IBM 3604Terje Mathisen
24 Jun 24 i  ii +* Re: ancient OS history, ARM is sort of channeling the IBM 3602Lawrence D'Oliveiro
24 Jun 24 i  ii i`- Re: ancient OS history, ARM is sort of channeling the IBM 3601Stephen Fuld
24 Jun 24 i  ii `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Thomas Koenig
24 Jun 24 i  i`* Re: ancient OS history, ARM is sort of channeling the IBM 3602Thomas Koenig
24 Jun 24 i  i `- Re: ancient OS history, ARM is sort of channeling the IBM 3601Lawrence D'Oliveiro
24 Jun 24 i  `* Re: ARM is sort of channeling the IBM 3602Stephen Fuld
24 Jun 24 i   `- Re: ARM is sort of channeling the IBM 3601Stephen Fuld
20 Jun 24 +* Re: ARM is channeling the IBM 3602moi
24 Jun 24 i`- Re: ARM is channeling the IBM 3601Lawrence D'Oliveiro
21 Jun 24 `* Re: ARM is channeling the IBM 3604MitchAlsup1
22 Jun 24  `* Re: ARM is channeling the IBM 3603John Dallman
22 Jun 24   +- Re: ARM is channeling the IBM 3601MitchAlsup1
22 Jun 24   `- Re: ARM is channeling the IBM 3601BGB

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