Re: ancient OS history, ARM is sort of channeling the IBM 360

Liste des GroupesRevenir à c arch 
Sujet : Re: ancient OS history, ARM is sort of channeling the IBM 360
De : SFuld (at) *nospam* alumni.cmu.edu.invalid (Stephen Fuld)
Groupes : comp.arch
Date : 30. Jun 2024, 17:30:27
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v5s173$jl70$1@dont-email.me>
References : 1 2
User-Agent : XanaNews/1.21-f3fb89f (x86; Portable ISpell)
John Dallman wrote:

In article <v5rcui$fqgj$1@dont-email.me>, tkoenig@netcologne.de
(Thomas Koenig) wrote:
 
Imagine a process which resides at a certain address.  It contains
code, data, and pointers to data.  Now you swap it out and want
to reload it.  You can use the same base address, then everything
is fine.  Or you can use a different one, where do the pointers
point, especially registers which contain addresses?
 
The /360 tried to solve this via base pointers, which all addresses
were supposed calculated relative to to.  Hence the RX and RS
instraction all had a base register + 12 bit offset for their
addressing modes - swapping out the base registers (if you knew
which ones they were, was this info in the executable?)  should have
worked.  But the SS instructions for decimal arithmetic did not have
base pointers, so that solution did not work in the general casse.
 
And only a 12-bit offset, to boot. I've read of systems with base and
limit registers, where all accesses were offsets from the base (or
separate base registers for code and data).

Yes, e.g. Univac 1108.



Real-mode 8086 code can
work that way, although I don't think you can limit the size of a
segment to less than 64KB. It looks as if /360 tried to construct
that kind of operation style from more general base register address
modes, but didn't do the job thoroughly.
 
Going to virtual memory from the start would have saved the
base pointer issue, and would have allowed 16-bit displacements,
also saving registers in the case where 12-bit displacements were
not enough.
 
Virtual memory was pretty new technology at the time, and required a
disk or drum. The central idea of /360 was having the same ISA across
a wide range of machines, and virtual memory wasn't affordable at the
low end at the time, AFAICS.

But IIRC even low end S/360s required a disk, at least to IPL(boot)
from.  But Virtual memory is more expensive than the hidden base
registers, as you need page tables. probably a TLB, etc.

 
So the problem wasn't with MFT memory management APIs or their
implementation, but that a /360 site had to find a set of partition
sizes that allowed for all the combinations of programs that they
needed to run simultaneously. This was inevitably wasteful of memory,
because each partition had to allow for the largest program that
could be required to run in it.
 
Is that correct?

That is correct for OS/MFT, but not for OS/MVT.



--
 - 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

Haut de la page

Les messages affichés proviennent d'usenet.

NewsPortal