show/tell me about DEC hardware (and x86 memory management)

The Something Awful Forums > Discussion > Serious Hardware/Software Crap > YOSPOS > show/tell me about DEC hardware (and x86 memory management)

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Farmer Crack-rear end posted:

what were Alpha systems mostly used for? high-end workstations, or servers?

both really, the first series of Alpha hardware (DEC 3000 AXP) shipped in both workstation and server variants (indicated by a trailing S on the model number), where the differentiator was whether they included a TURBOchannel video card and were pre-set to boot to a serial console or video/keyboard/mouse console

they didn�t even ship distinct manual sets, instead you�d get a manual set for �DEC AXP 3000 Model 400/400S� (this is what I have)

Alpha was the first CPU to push speeds into the hundreds of MHz a couple years before its competitors, though that didn�t necessarily translate to that much of a performance advantage given the simplicity of its instructions even relative to other RISC systems

Alpha also supported very large memory on workstations for the time, which is why the first ones I saw were being used for things like computational chemistry; I have a model 400 in the maximum configuration at 512MB, while the floorstanding 500 (introduced at the same time) supports up to 1GB

# ¿ Jan 11, 2022 04:54

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# ¿ May 22, 2024 16:35

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Farmer Crack-rear end posted:

i've never seen an alpha system myself. do any of the vintage hardware folks around here have one? what were they like to use? what was good and bad? what were they good at?

I have several, though not a lot of pics

here�s my DEC 3000 AXP Model 400, from the first series of Alpha workstations and servers, booted into OpenVMS 7.1 as a workstation

I also have a couple of AlphaStation systems, an AlphaServer 1000A, and an adorable little AlphaServer DS10e which I finally got a video card for so it can be used as a workstation

as for what they were like to use, they were �just� a workstation, but compared to their contemporaries they felt really loving fast

what was more unique about them was that DECwindows was a complete environment very early on (pre-CDE) and reasonably productivity-focused so it even had tools like a paint app and DEC even made a MacWrite clone (DECwrite)

DECwindows started life on the VAXstation workstations, but was kept high-level and built for both VMS and Ultrix on them and so was easy to bring to the MIPS and then Alpha lines too, and DEC really thought they�d be able to put X terminals on the desks of non-technical staff to run productivity software instead of using PCs, which wasn�t that insane when PCs were also a couple grand each and ran DOS and the idea of a network was new, but by 1992 the writing was on the wall

it still meant that OEMs using things like an Alpha workstation or server as a PostScript rasterizer for phototypesetting would actually build monitoring applications that fit into the environment, instead of having their own wacky interface. that�s what my 400 was used for before I got it

# ¿ Jan 11, 2022 05:10

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

I need to set it up again and install the fancy ZLX-series 3D card, it has an i860 on it!

# ¿ Jan 11, 2022 11:14

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

you want to see a really weird and cool architecture, check out the PDP-8

the personal computer revolution could have been twelve-bit

from the quick reference card:

code:

AND      0000  logical AND                         2.6
TAD      1000  2's complement add                  2.6
ISZ      2000  increment and skip if zero          2.6
DCA      3000  deposit and clear AC                2.6
JMS      4000  jump to subroutine                  2.6
JMP      5000  jump                                1.2
IOT      6000  in-out transfer                     ---
OPR      7000  operate                             1.2


 _0___1___2_ _3_ _4_ _5___6___7___8___9___10__11
|           |   |   |                           |
|OP CODE 0-5| IA| MP|          ADDRESS          |
|___|___|___|___|___|___|___|___|___|___|___|___|
              |   | |            PAGE           |
              |   |  --->  RELATIVE ADDRESS <---
              |   |
               ----------- INDIRECT ADDRESSING
                  |         0 = DIRECT
                  |         1 = INDIRECT
                  |
                   ------- MEMORY PAGE
                            0 = PAGE ZERO
                            1 = CURRENT PAGE
            
Memory Reference Instruction Bit Assignments

that�s it, that�s the instruction set

(OPR does a hell of a lot of heavy lifting but still not as much as you might think, it�s extremely RISC)

# ¿ Jan 12, 2022 07:23

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

it�s like a couple hours to write a PDP-8 emulator in C, it�s awesome

# ¿ Jan 12, 2022 07:28

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

also I/O is handled as part of the instruction set so you basically have putc() and getc() in hardware which means you can even get pretty far in (1) loading, (2) running, and (3) reporting the results from the actual DEC diagnostic tests in those couple hours

# ¿ Jan 12, 2022 07:30

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Farmer Crack-rear end posted:

where did DEC go for chip fab? did they have their own plant, did they hire others?

I believe they had their own fab in the 1970s-80s at least, don�t know about the 1990s and beyond

# ¿ Jan 18, 2022 02:34

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Kazinsal posted:

I've written code for a PC/XT and it's wonderfully quaint. everything's so slow you don't really have to worry about timing and synchronization all that much. kinda thinking about doing a quick and lovely unix clone for the 8088 as an extremely elaborate and niche april fools joke

it�s a decent platform for that, that�s what Andy Tanenbaum & crew did to make MINIX and another group did to create PC/IX

I�d suggest a DEC RT-11 or HP RTE or MPE clone just to be different, should be just as easy

or heck TOPS-10 or TOPS-20 since those had lots of fans

# ¿ Jan 19, 2022 22:01

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

rjmccall posted:

the times just had a clue like �aunt and uncle�s little girl� for �niece�, so

spoiler that poo poo man

# ¿ Jan 20, 2022 00:28

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Zlodo posted:

there was this cool interview of some of the team that designed the 68k at Motorola and they said IBM chose the 8088 over the 68k at the time specifically because of the 8 bit bus since it helped make all the hardware cheaper (and they could use existing peripheral chips designed for 8 bit CPUs)

IBM asked Motorola to do the same and they refused, the Motorola guy in the interview said that in retrospect it would have been actually quite easy to do (and they did do it eventually, is was the 68008)

that�s a weird assertion since the 68000 has had 6800-series peripheral support from the start

my understanding was that Motorola didn�t have second sourcing and full qualification set up early enough for IBM�s adoption

on the other hand there�s still just more poo poo to route, and you still always had to use 16 bits worth of RAM and ROM until the 68020�s dynamic bus sizing support

# ¿ Jan 20, 2022 00:44

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Gun Metal Cray posted:

oh man, I wish I had the time to spare to do something weird like this

what would be a good simulation setup to get started?

SIMH works pretty well, it has decent emulation of tons of old architectures including the PDP series and VAX, HP 2100 (earlier version of HP 1000, suitable for RTE) and HP 3000 (an earlier version, suitable for MPE IV) and there are kits for some that will let you get something up and running quickly

I just wish SIMH had more of a �detached� console; it uses stdio for both its own console and the simulated system�s console, which isn�t great if you want to a simulator as a service; ideally it�d have distinct concepts of log output, simulator console I/O, and simulated system I/O, and allow all three to be wired up independently via a system�s ini file

# ¿ Jan 24, 2022 10:43

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

epitaph posted:

wasn�t NT developed by ex-DEC people?

Dave Cutler was the primary architect of both

quote:

i remember one of the architects expressing particular scorn at unix for its i/o model (DEC had famously hitched their wagon to VMS)

VMS has a very good I/O model, especially for running a multi-user system on what would be considered a paltry amount of RAM for a server even 25 years ago

I set up a VAXstation 4000 Model 60 emulator with the final VAX release of VMS and all the patches and development tools so I could build and fool around with The Monster and it was all really smooth

my real VAXstation 4000 VLC has a whopping 24MB of RAM and while it�s not like it�s super fast, it�s perfectly serviceable for both single-user graphical login or multi-user network login, about the only downside is no direct SSH (since even with an implementation it�d likely be too slow and low-memory to negotiate a connection)

a lot of the classic Mac OS follows a similar �asynchronous, parameter block specified I/O with completion handlers� pattern to VMS and NT and it works quite well for keeping what�s actually a rather slow system responsive, it�s no wonder that UNIX async I/O tends to look similar as it tries to improve performance

# ¿ Feb 1, 2022 07:11

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

feedmegin posted:

...my first PC at uni running Linux had 16 megs of RAM and that was actually twice what a low end system at the time would have. This was a time when EMACS was known as Eight Megabytes and Constantly Swapping because that was a lot of memory at the time.

You can't fit ssh in 24 megs?!

you probably can but I wouldn�t expect a typical sshd to care enough about overhead to work within such limits

the real issue there is CPU speed, it�s like 14 MHz, and I�ve seen comparable CPUs cause negotiation to time out

# ¿ Feb 1, 2022 16:53

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

most 64-bit platforms are LP64, where long-integer and pointer types are 64-bit and the rest are 32-bit and there are safeguards like marking the first 4GB of the address space as not accessible and so on

VMS on Alpha was and IA64 was essentially an ILP64 platform (which they described as IP64) where it just assumes that you know what you�re doing if quantities go over 32 bits, and thus has continued to the new x86-64 version

also most of VMS is still written in VAX assembly language, but the DEC macro assembler, MACRO-32, is so insanely full-featured that they retroactively decided it was its own language and just wrote a new backend instead of rewriting (and the rest was written in BLISS-32, which is pretty much isomorphic to C, so that just needed a new backend too)

for the new x86-64 version, they�ve rewritten the MACRO-32 et al backends one last time, for LLVM, so they could hypothetically target anything LLVM has a backend for, such as, say, ARM64

and here�s the thing: VMS itself was partially a port of the 16-bit PDP-11 operating system RSX-11, which was mostly written in MACRO-11, and the first few major VAX models had user-mode PDP-11 compatibility in hardware and many of the system utilities were the RSX binaries

when the PDP-11 compatibility hardware was eliminated and the last utilities fully ported to MACRO-32 or BLISS-32, they just switched from hardware to software implementation of the compatibility and made it a layered product you could license and install in case you still had software you needed to run, and it still works on the final VAX version of VMS

so, in essence, DEC did Intel/Microsoft backwards compatibility better and almost a decade earlier�

there are still people mad that VMS 8.4 doesn�t support VAX, and there are more people mad that 9.1 is only for x86-64 instead of running on all of Alpha, IA64, and x86-64, on all the hardware those have ever supported

(which, granted, 8.4 will run on the very first Alpha and Itanium, and 7.3 on the first VAX, so they have a better reason than most to be disappointed�)

# ¿ Feb 2, 2022 07:48

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Sweevo posted:

the hard drive being missing is a pain because i've heard VAXes are pretty picky about what drives work. the boot drive must be 1.05GB or less for example

not a big deal since the SCSI2SD, you can set the size and identifier to match what the DEC bootstraps expect and it�ll just work

RZ26 works for a ton of stuff

# ¿ Feb 15, 2022 10:49

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

Kazinsal, are you going to set up VMS on SIMH initially and then transfer the disk images to an SD card to boot on the VAX?

if so be aware that SIMH will spend an extra block or two to the image with its own metadata rather than put that in a separate file, but it�s easy to deal with since it�s just an append

this way you can get VMS 7.3 set up with all the layered products etc. and maybe even get MONSTER-Helsinki set up if you want to run the YOSMUD

# ¿ Feb 15, 2022 22:29

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

(I can provide the simple tweak needed to build MONSTER-Helsinki 1.0.6 with the final VAX Pascal compiler)

# ¿ Feb 15, 2022 22:30

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

how about some HP hardware?

my HP rp2430 now believes it�s an rp2470 and will boot MPE/iX 7.5

# ¿ Mar 2, 2022 13:17

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

MPE/iX normally doesn�t boot on a system that�s not specifically enabled for it by a few values in EEPROM (�stable storage� in HP terms) which let HP sell the same hardware badged as HP 3000 for two to five times what they charged for it badged as HP 9000 and running HP-UX

I had to interrupt the boot process, which then let me access a secret tool in the Service menu off the main boot menu, and run that to change my hardware model and part number, some model strings that are checked at boot, and the bit that says whether MPE is allowed to run

here�s an example of how the process works

# ¿ Mar 2, 2022 22:26

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

oh and the main reason to tell my rp2430 it�s an rp2470 is because, while the systems used the same main logic board and ROM, the rp2430 is a single-CPU system with a 2GB RAM ceiling and three PCI slots while the rp2470 supports one or two CPUs, all five PCI slots, and up to 8GB of RAM�it�s just held back by the model string

# ¿ Mar 2, 2022 23:01

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

it required way way too much from compilers to actually exploit well for random software written in C

business software written in COBOL may have fared better, I know FORTRAN code did; my rx2660 with DEC FORTRAN running some numeric benchmarks did really impressively for the era in which it was made, on par with some much newer x86-64 hardware

people were also able to make databases fly and the HP 3000 people were legit pissed that after promoting it to select customers, HP shelved the work they were doing to port MPE/iX to Itanium (along with shelving the entire HP 3000)

# ¿ Mar 4, 2022 09:48

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

The ROM may not know about RZ35 and be hesitant to boot from it automatically but trust the operator. You could reconfigure your SCSI2SD to have all the disks start at the same blocks as now, but have the one you boot from claim to be an RZ26 (sized to match, of course) and it should Just Work.

# ¿ Mar 15, 2022 01:28

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

bitsavers is your lord and savior

# ¿ Mar 15, 2022 01:51

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

fast emulated VAX running VMS NOTES and MONSTER (the MUD ancestor)

with SA-account-derived auth via LDAP or something, and no user directories so users can only really put stuff in the shared notesfiles and join MONSTER

# ¿ Mar 16, 2022 08:02

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# ¿ May 22, 2024 16:35

eschaton: Mar 7, 2007; Don't you just hate when you wind up in a store with people who are in a socioeconomic class that is pretty obviously about two levels lower than your own?

want to give InterLisp-D a try on an emulated Xerox workstation?

set up an account online.interlisp.org and you even get a persistent workspace

the square-dance crew who used to come into the bar & grill across the street from my place, pre-COVID, used to include the last owners of Medley

I asked after them with one of the folks from the crew not too long before the pandemic, because I was hoping to acquire the InterLisp IP and release it; my understanding had been the person who owned it was a bit of an rear end, but eventually disposition fell on a relative who didn�t have their head up their rear end and who worked with a number of people to enable this to happen

it�s pretty awesome, and mostly a faithful representation of what it�s like to use on real hardware�any misrepresentation is in the near-instantaneous performance, compared to a 16-bit bitslice microcoded CPU whose architecture was derived from the Nova, or the slightly more abstract virtual machine built atop of it

incidentally, the emulation they�re using should also be able to run the Smalltalk and ViewPoint environments, I hope those can also be hosted and shared; Smalltalk in particular is such an amazing system to use, everything is right there and malleable like putty, even moreso on a Lisp Machine

# ¿ Mar 16, 2022 10:13

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