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virtual memory 4474
Anne & Lynn Wheeler After our previous discussions, I looked high and low for any details on the grenoble system, and fifo...
virtual memory 4475
some posts in previous incarnation of this thread from the original cp67 that was installed in the univ. last week jan68 used effectively a variation on fifo; it scanned storage looking for pages in state...
virtual memory 4476
Anne & Lynn Wheeler As I understand it, one key issue is what happens after the page falls out of the working set...
virtual memory 4477
note that was what i did in the late '60s in global LRU ... and it was retained in the grenoble local LRU implementation ... the...
virtual memory 4478
so, I've told the story of how MVS decided to bias the LRU replacement algorithm in favor of non-changed pages ... because there was lower overhead and less latency ... than compared to when...
virtual memory 4479
the other thing that was starting to happend by the second half of the 70s was things were starting to shift...
virtual memory 4480
another characteristic of the real memory resource vis-a-vis disk resource trade-off was the original os-360 design using CKD DASD...
virtual memory 4481
Brian Inglis Hard to tell exactly what was going on then. In Belady's "A study of replacement algorithms for a virtual-storage computer" from 1966 (I just...
virtual memory 4482
On Mon, 15 May 2006 19:25:53 +0000 (UTC) in alt.folklore.computers, The accessed bit should be in the hardware just...
virtual memory 4483
possibly you are thinking of simulation of LRU for things like database caches ... rather than processor paging that...
virtual memory 4484
clock and global lru uses an LRU approximation ... that kind of sorts pages into two categories ... those that have their reference bit used since the last examination-reset, and those that haven't...
virtual memory 4485
ref: besides the numerous different variations on LRU approximations, "true" LRU implemented in simulators ... there was also belady's "OPT...
virtual memory 4486
Brian Inglis FIFO, like all these algorithms, tries to predict future behaviour from the past. LRU guesses that pages that have not been used for a...
virtual memory 4487
actually LRU replacement strategy has the property that it can degenerate to FIFO replacement strategy ... i.e. program behavior that cycles through memory location. An example is the apl-360 memory management...
virtual memory 4488
old post discussing how hardware address translation worked on trout 1.5 (3090), including email from fall of '83...
virtual memory 4489
re: "811" (named after 11-78 publication date on the architecture documents) or 3081 was considered somewhat of a 155-158 follow-on machine ... being much more of a m'coded machine. "TROUT...
virtual memory 4490
Sorry. It was better that you looked it up for the precise description; I don't write well...
virtual memory 4491
cp67 use to support a limited number of shared pages in this "64kbyte" segment option (16 4k pages) in the two level table structures. a virtual address space was represented by a "segment" table. segment...
virtual memory 4492
as mentioned in the previous post some of the work that i had done in the 60s as an undergraduate for...
virtual memory 4493
Right. All you had to was zero the word, or half word, or bit, that pointed at the index of...
virtual memory 4494
in this previous incarnation of the thread-subject from 7aug2004 there was the issue of paging virtual memory being...
virtual memory 4495
Brian Inglis Lynn's exposition is not always easy (at least for me) to follow completely, but his expansion on this topic in other...
virtual memory 4496
Jan Vorbrüggen Yeah. The problem on the VAX was that the WS list was an array sized by WSMAX parameter that resided inside the process header...
virtual memory 4497
I never had that ... dating back to my original implementations in the 60s. working set size was mechanism for limiting over commit of real storage and...
virtual memory 4498
Bill Todd I found such studies, which appear to show that VMS's mechanism is within, by looking at a...
virtual memory 4499
presumably this refers to "local" LRU as opposed to global-system LRU. what was their basis for "LRU" ... was it at the per instruction reference (updating the...
virtual memory 4500
Brian Inglis ... Perhaps it went to the same place where people who are unwilling to accept actual data in studies whose results don't conform to their preconceptions banished it. Of...
virtual memory 4501
one of the things that some of the paging simulation work done at the science center looked at the trade-offs of different sized pages...
virtual memory 4502
re: part of the instruction storage ref-change trace and paging simulation was also the program reoganization work that was mentioned previously D...
virtual memory 4503
On Thu, 01 Jun 2006 17:07:33 -0400 in alt.folklore.computers, Bill The comment was meant to be general...
virtual memory 4504
Brian Inglis A somewhat random comment to throw in if it wasn't intended to apply...
virtual memory 4505
On Fri, 02 Jun 2006 01:16:04 -0400 in alt.folklore.computers, Bill Of course it was intended to apply. As Lynn Wheeler has pointed out elsethread, there seemed...
virtual memory 4506
On Fri, 02 Jun 2006 01:16:04 -0400 in alt.folklore.computers, Bill Of course it was intended...
virtual memory 4507
Brian Inglis You don't suppose that could possibly have been because advances in the state of the art often appear earlier in academic papers than in commercial...
virtual memory 4508
the mid-range 370 4341 had somewhat similar issue. i've posted the us & world-wide sales for vax, broken out by...
virtual memory 4509
previous post mentioning 370s shipping with both 2k and 4k virtual page support and comparison of operating systems in different...
virtual memory 4510
Anne & Lynn Wheeler It seems unlikely that working-set implementations were anywhere nearly as mature as LRU was at that time, doesn't it? I doubt that...
virtual memory 4511
Brian Inglis That number came from zooming in on some lines on graph in a fuzzy copy of a document. There are multiple lines on the graph, covering multiple scenarios, and...
virtual memory 4512
fOn Mon, 15 May 2006 22:38:39 +0200 in alt.folklore.computers, Terje Pool-subpool allocation seems advantageous in situations where, as with OS control blocks, you sometimes have high rates of de--allocation and sometimes...
virtual memory 4513
science center had ported apl-360 to cms-apl. apl-360 had basicly its own subsystem monitor, terminal handler...
virtual memory 4514
cp67 kernel initially implemented bestfit ... an issue was storage fragmentation and long chains of "free" blocks ... production operation frequently would get to several hundred (or more) available blocks ... releasing a...
virtual memory 4515
the post did describe a case where virtual memory was used to address fragmentation problem some subsequent drift on this thread in a.f.c. i had done a bunch of the...
virtual memory 4516
the earlier 3033 had a hack on this in the late 70s related to 24-bit addressing. instructions were 24-bit both real addressing and virtual...
virtual memory 4517
On Fri, 2 Jun 2006, Andy Glew Ooh... :) This is just the kind of thing I'd love to learn more...
virtual memory 4518
Andy Glew You're certainly in a far better position to answer that than I am, but my...
virtual memory 4519
Jan Vorbrüggen VMS on Alpha could binary recompile VMS-VAX applications and-or emulate the VMS-VAX environment as needed to run old code. The OS proper had little knowledge that this...
virtual memory 4520
Doing PAE properly (allowing all interesting data structures to grow above the direct mappable area) is very very hard. It gets worse the bigger than VA:max managed memory...
virtual memory 4521
Andi Kleen I fully agree. I should have been clearer in specifying that the "easy...
Very slow booting and running and braindead OS's
Faint memories, I hope I'm not slandering any systems too badly, but can anybody verify and expand this list of doggish OS's?: 1130-CAI A multi-terminal Computer Aided Instruction OS for the 1130, using...
Very slow booting and running and braindead OS's 4523
Of course not (heck, we supported thousands of concurrent TIP users on much lesser 1100- and 2200-series mainframe boxes at the airline I used to work for). The "40-50" number is simply the largest...
Very slow booting and running and braindead OS's 4524
On Sun, 17 Sep 2006 17:28:13 -0400 in alt.folklore.computers, Sorry to follow-up to myself, but I see I didn't finish. The...
Very slow booting and running and braindead OS's 4525
No, I counted one user with multiple sign-ons as one user. If I would have been counting jobs or processes, I would have stated such. FWIW, though, I...
Very slow booting and running and braindead OS's 4526
Here in alt.folklore.computers, A lot also depends on how you count "users", on the types of activities those users are performing, and...
Very slow booting and running and braindead OS's 4527
All kinds of things. The OS-2 desktop itself uses something like 35 concurrent threads, and I tend to run a fair number of things in the background. A...
Very slow booting and running and braindead OS's 4528
Yup. Here near the Jersey Shore in the summer and fall we lose power in thunderstorms and when any drunken college kid takes out a telephone pole along the...
Very slow booting and running and braindead OS's 4529
So, if you get junk hardware, you get a maintenance problem. What else is new? If over a year and a half you...
Very slow booting and running and braindead OS's 4530
THat's easy. You have kids. You have friends. You forget some gear and need to...