test-drb February 2010

test-drb@ccmp.vtda.org

175 participants
221 discussions

by james＠jfc.org.uk

I just watched Season 1, Episode 3 of the Monkees where they have several shots of an SDS Sigma 7. This was in 1966, so it can't have been long after the release of the Sigma 7. I'd not seen it mentioned here before and I thought some might be interested... http://www.starringthecomputer.com/feature.php?f=333 -- James F. Carter www.jfc.org.uk www.podquiz.com www.starringthecomputer.com

16 years

VAX graphics

by bqt＠softjar.se

"e.stiebler" <emu at e-bbes.com> wrote: > Johnny Billquist wrote: >> And I dare say, that picture have higher resolution, and more depth than >> my simple calculation above used. > > No, it should be just 512x512x8. Don't forget that you are watching > youtube in a lousy resolution. You are right. She even says in the beginning that it's 250,000 pixels. Assuming they take a little liberties to simplify things, that would mean 512x512. Looking at the first perspective city picture, you can see that he has a palette of 256 shades to blue to pick from (ranging from black to white). It might be that the graphic system have a color palette then, since obviously, there are other colors than blue possible, but none others are shown there. Or else they have a 24 bit pixel depth, which would be very impressive. But any way you look at it, my comment still stands. With a serial line running at 19200 bps, it would take about two and a half minute to draw a picture, at the best of time. I dare say we can safely assume it's not a serially connected terminal (even ignoring that I don't think I've ever seen or heard of a serial terminal with bitmap graphics with a resolution close to this). Looking more at the video. There are no visible clues at all that I can see as to who actually manufactured the graphics system. The system definitely are running some kind of Unix, though. Anyone who recognize the tablet? It is after all in focus quite a lot. > And we used a grinell system 1981 already (pdp11) which had 512x256 (not > sure it was 512x512). 8 bit is sufficient to show what he is doing on it. Never heard of grinell. But I have a VSV21 here. 640x480 pixel resolution. Unfortunately only 4 bitplanes. But it's a very fun graphic system for the PDP11 anyway... And later than 1981, but made by DEC. Oh, and that's for the Q-bus... Unibus graphic systems are rarer... Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol

16 years

Barden programming books (was: Re: TRS-80 bootable media request)

by ethan.dicks＠gmail.com

On 2/26/10, Mark Tapley <mtapley at swri.edu> wrote: > At 17:20 -0600 2/25/10, Mike L. wrote: >>"More TRS-80 Assembly Language Programming", by Bill Barden > > A comment and a question: I found on eBay the CoCo Assembly > book by the same author. It's clear, an enjoyable read, and does a > good job of introducing programming, the debugger/assembler > implemented on the cartridge, and 6809 assembly language in a simple, > easy-to-understand progression. I may have to keep my eyes out for that one. I'm much less informed about the 6809 than any of the other contemporary processors. > However, it seems to me to give really short shrift to what > the 6809 designers considered to be very important features of the > processor. Position independent code is barely touched on, there are > a lot of what looks to me like kludgy programming techniques, the > most advanced software-management tool discussed is a flowchart (and > then there's no useful example of how to use them), the multiple > pointer registers are abused as 16-bit counters rather than as > indexing pointers, and there are many similar examples. Hmm... I haven't read anything by Barden, so I'm merely commenting on your comments, but I do remember that back in the day, besides a "better" register scheme, the one thing that really made the 6809 stand out (from my 6502 world) was its ability to render position-independent code. I didn't need it often when I was programming the 6502 daily, but occasionally, I did wish for it. Perhaps the lack of attention to that in the book is due to a lack of perceived utility for it? When the 6502 and Z80 and 6809 ruled the earth (or at least the hobbyist corner of it), multitasking operating systems weren't the norm. I know OS/9 stands out, but until you jump up to early UNIX super-micros, there's not much else in the field that was commonly available (the PDP-8 had RTS-8, but compared to a basic OS/8 setup, RTS/8 was strange and rare). The vast majority of micros had "operating systems" (by a very wide definition) with fixed-position memory maps. There was little need to be able to shuffle your code from one spot in memory to another. Even on larger systems, like the PDP-11, MMU hardware did that sort of mapping for you (despite the fact that PIC is easy to write for the -11). As for the lack of "advanced software-management tool[s]", most of the books that I've read from the late 1970s and early 1980s fall into that category. I don't think I learned anything "better" than flowcharts and coding sheets until I hit the minicomputer world in the mid-1980s (it sure wasn't any different when I took my first programming course in college in 1984 - flowcharts were a mandatory part of the homework and were graded quite rigorously). > Does anybody else have the same take on this? I was thinking > about using it to teach programming to one or more of the kids, but > it seems to me that I'd rather find something a bit more > structure-oriented, and less likely to use "tricks". By the late 1980s, I remember a change in the weather with articles in Amiga-centric magazines on programming the 68000. See if you can find Transactor magazines (or PDFs of them). Those might be "modern" enough in their approach to feel more friendly. The instruction set's not the same, but code organization and concepts are analogous. > Am I just spoiled from having read the 6809 programmer's > guide and the (somewhat snooty-sounding) Byte article on 6809 design > and introduction? Perhaps. With 1970s docs, my feeling of remembering those days is that 8080 and Z80 tutorials and guides were "stiffer" than 6502-related material, but I'll easily admit those memories are somewhat biased because I spent lots more time seeking out and reading 6502 publications in depth. The 6809 stuff, though, kinda went by unexplored by me since I had no hardware to tie to it. -ethan

16 years

flowcharts and teaching programming/was Re: Barden programming books

by c.murray.mccullough＠gmail.com

I began programming IBM, CDC and Amdahl machines in June 1970. All assignments at the Computer Institute of Canada were graded according to the accuracy of the flowchart and the initial box as Chuck states. COBOL and other languages employed at that time employed gotos; it was a sign of sloppy programming according to purists and professors/instructors but gotos usually solved complex junction problems in an elegant fashion. BASIC and 'Small-C' used them to the same effect in the microcomputer world of late 70s. Early programming books are getting scarce yet magazines of that era had programming projects and got many of us interested in advanced programming versus machine-language programming; it beat flipping switches and assembler programming of early to mid-70s machines! Murray--

16 years

Problem getting non-blocking sockets going on BSD 2.11

by toby＠coreware.co.uk

I'm in the midst of writing a MUD for PDP-11s running under BSD 2.11 and have run into a problem getting non-blocking I/O working. I initially wrote a simple test program to setup a non-blocking socket and accept connections then echo back anything typed to all connected sessions. This worked fine. However now I've placed the exact same code into my MUD development, the sockets are blocking. I've got the following in my setup of the socket: /* Set socket to non-blocking */ if( ioctl(s,FIONBIO) == -1 ) { printf("Error ocurred"); } which I believe should make the socket non-block and when I run up the code it doesn't throw a failure on the ioctl, however the socket definitely remains in blocking mode. Anyone have any ideas? I've been scratching my head on this one for days now I've put all the source I've written thus far here: http://www.pdp11.co.uk/wp-content/retromud/ Sorry if the code is a bit cludgy, but I've not programmed C for about 15 years and its only just coming back to me! The file comms.c is where most of the socket actions occurs. All the best, Toby

16 years

DEChamonicas

by wdonzelli＠gmail.com

I have a bunch of DEC H3104 Harmonicas - the little boxes that fan a Dshell connector out to 8 MMJs. Is there any interest in these, or should I just throw them in the scrap board pile? I have some of the mounting plates for these as well. -- Will

16 years

Museums

by hachti＠hachti.de

> I am not so sure that it is necessarily the case that people lose interest > in things that pre-date their own lifetime. I try to collect only stuff that's older than me - so end 1978 is my limit :-) There are some newer things like 11/23 or late additions to older machines. But all in all I like the fact playing with gear from the time before me. But I can understand the concerns. I also assume that the prices for the good scrap won't rise... Kind regards, Philipp

16 years

OT: Old SAC film

by cclist＠sydex.com

Since "Wargames" wa mentioned, I thought I'd post this link to an old PR film from the Strategic Air Command. Only a brief shot of computing gear on reel 1, but lots of teleprinters, teletypes and comm consoles. About 18 minutes long. The first two of three reels are of high quality; for some reason, the third one is not. http://www.gwu.edu/~nsarchiv/nukevault/ebb304/film03.htm Cheers, Chuck

16 years

Lusent SCSI things

by wdonzelli＠gmail.com

More weird crap. I have a couple of modules - Lucent 990C01407410 (I think) - that are doing me no good, and will end up as scrap soon. They seem to be Differential In to Single Ended Out converters. They are dated 1997. Any ideas as to what machine used these? 3B series add-on? Anyone need them CHEAP? -- Will

16 years

DOS versions compared

by lproven＠gmail.com

I've just been setting up a couple of old PCs to go off to the ComputerAid charity. These are junkers: 1 ? Athlon XP 1800+, 640MB RAM, 1 ? Athlon XP 1700+, 768MB RAM; I've fitted both with 20GB hard disks, a DVD-ROM and a CDRW. Remarkably, this level of kit is what some term "skipware" now - just about the lowest spec that the charity will take. I tried both Linux Mint & TinyXP on them, but both hit snags, and I don't want to spend hours troubleshooting, so I downloaded FreeDOS 1.0 and bunged that on. Remarkably, FreeDOS now comes on CD - there is 150MB of it! The install is pretty fiddly, although it all works. On one of them it even autodetects a PCI Ethernet card & goes online. And to my amazement, I discovered that I'm credited in the README file for the bundled OpenGEM GUI. I am a bit torn over FreeDOS, though. I used to be a big fan of DR-DOS, back in the day, although in the end I saw & deployed far more MS-DOS boxes. :?( But FreeDOS seems to have surpassed both the standalone editions of MS-DOS (which ended at MS-DOS 6.22, although PC-DOS 2000 advanced on that in a few areas). FreeDOS boasts large (20GB) partition/filesystem support, FAT32, Win9x-style Long File Names, native networking, TCP/IP, CD-ROM & writer support, comes with dev tools, web browsers, email, games, all sorts. It's a hell of a DOS system! I was wondering if anyone here had used it in anger at all? How does it hold up compared to MS-DOS, the embedded DOS in Win9x, IBM PC DOS, DR-DOS in its commercial or FOSS incarnations...? -- Liam Proven ? Profile: http://www.linkedin.com/in/liamproven Email: lproven at cix.co.uk ? GMail/GoogleTalk/Orkut: lproven at gmail.com Tel: +44 20-8685-0498 ? Cell: +44 7939-087884 ? Fax: + 44 870-9151419 AOL/AIM/iChat/Yahoo/Skype: liamproven ? LiveJournal/Twitter: lproven MSN: lproven at hotmail.com ? ICQ: 73187508

16 years

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test-drb February 2010