test-drb

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101090 discussions

by wilson＠dbit.dbit.com

I've just put a bunch of TSS/8 stuff at: ftp://ftp.dbit.com/pub/pdp8/tss8/ This is mostly a bunch of doodads I wrote when I had a TSS/8.24 system running briefly (from late 1983 when I bought it, to mid 1984 when the RS08 disk became too unreliable for the system to stay running), including an unfinished VT52 text editor and a pretty good start on a FORTH compiler. But also there's the source to the TSS/8.24 monitor itself, which I typed in from a borrowed listing (so some typos may have gotten through) and then lost on DECtape for many years. FYI in case anyone else ever needs this, TSS/8.24 DUMP tapes are really simple: The first and last blocks of each 1474-block DECtape are not used. Each 4 KW "track" (actually two tracks on an RS08) is stored as 32 (decimal) consecutive DECtape blocks, starting at block 1. Only the first 128 words of each block are used, and they're all recorded in the forwards direction. So up to 46. consecutive "tracks" fit on each DECtape, and you just concanate all the "tracks" from all the DECtapes in the set to get the disk. It starts at the very beginning of the disk, and even the swap tracks are saved. Anyway the ever-further-behind-schedule new version of my PUTR.COM utility for DOS will include at least read-only support for TSS/8.24 disk images (as long as they're similar to mine, i.e. SEGSIZ=256 and new enough to support the hack where filename extensions are added by encoding them in the high 5 bits of the protection code). It will read and write TSS/8 PUTR.SAV DECtapes too (which turn out to use the OS/8 file format, but with 11:1 interleave, TSS/8 style ASCII encoding, and the weird 5-bit filename extensions). Speaking of DECtape, does anyone know anything about PS/8 DECtapes? I have one image from David Gesswein which is supposed to be from PS/8, and it looks just like an OS/8 tape except that it uses only every other block for the first 256. OS/8 blocks on the tape. After that I can't figure out *where* things pick up again, I suspect some of the blocks may have been recorded backwards (like with TSS/8). Sound familiar to anyone? The tape has OMSI's hack of Edu-30 (?) BASIC on it and somewhere in there, there's a blurb about how proud they are of having sped things up on DECtape systems. So I suppose it's possible that this is just an OMSI-hacked DECtape driver and nothing to do with PS/8 at all. But then again maybe OMSI just changed how BASIC accesses the tape through the vanilla driver so it really is a PS/8 thing. Help!!! John Wilson D Bit

25 years, 11 months

Altair parts substitutions

by RCini＠congressfinancial.com

It's that time of year again, when I think about designing an Altair/IMSAI work-alike. Now that I have the ability to generate schematics/layouts, I may actually try it. Anyway, some parts have become scarce, so I would have to use substitutes. For example, Jameco no longer carries the 8T97 buffer/driver. As I recall the 8T97 is an LS373 without the inverter on the gate *and* is faster and has a higher drive current. I've heard that the MC6887 is a sub, but I can't find a datasheet on it. The 8101 dual-port 256bx4 RAM is no longer available, but Jameco has a 5101 which looks like a likely sub. I would forego this type for a larger SRAM, but I guess that it too would have to be dual-ported. I need to look at the schematics for an S100 memory board. Someone on-list did a design for his own clone, but I can't remember who it is. I'm sure that it can be done cheaper than Tom Fischer's IMSAI-2 though. Rich

25 years, 11 months

Altair parts substitutions

by allisonp＠world.std.com

>> Anyway, some parts have become scarce, so I would have to use substitutes. >> For example, Jameco no longer carries the 8T97 buffer/driver. As I recall >> the 8T97 is an LS373 without the inverter on the gate *and* is faster and > >I thought that the 74LS367 and 74LS368 (the latter being the inverting >one) were almost direct substitutes. I think the 8Txx parts can drive a >heavier load, but I doubt if this will cause problems in an Altair/Imsai Tony is right. 8t97 and 8t98 are close to the 74LS367 and 74ls368 in drive and exactly the same pinout. >The '373 is an octal transparent latch (with 3-state outputs) and is not >the same thing at all. the '373 wasn't available when the altair was new. >> has a higher drive current. I've heard that the MC6887 is a sub, but I can't >> find a datasheet on it. >> >> The 8101 dual-port 256bx4 RAM is no longer available, but Jameco has a 5101 >> which looks like a likely sub. I would forego this type for a larger SRAM, That would work, the difference is the 5101 is cmos and the 8101 is mos. >I can't find the 8101 on any of the S100 card schematics I've looked at, >so I wonder what on earth it was used for. try 2101. the first ram card was a 256byte one using 256x4 parts if memeory serves. The denser cards were 2107/TMS4060 4kx1 Dram based. He may have meant seperate Input and output like the 2102 (1kx1). Allison

25 years, 11 months

ASCII pictures available

by lemay＠cs.umn.edu

http://afterhours.lpmud.com/~james The tar file contains directories, which then contain files compressed with the unix 'compress' command. 'disk1' and 'disk2' contain the big multi-overprint files that came from an old magnetic tape i read back in the 80's on a Control Data mainframe. You will note that you can fit disk1 and disk2 onto 2 floppy disks, and that they also contain a DOS binary program for uncompressing the files, if you dont have unix access. the vt100 directory is just some old VT100 text animations, and the small ascii directory came from some ftp site over 10 years ago. -Lawrence LeMay

25 years, 11 months

Vancouver, Cal's Computer Warehouse?

by CLASSICCMP＠trailing-edge.com

>Anybody up in Vancouver familiar with this place? > >They have a service manual for my NEC Silentwriter 2 model 90 on eBay right >now, but I am also curious about them in general. > >http://www.goseecal.com/ > >Cal's Computer Warehouse Inc. >3083 Grandview Hwy. >Vancouver, B.C., V5M 2E4 >Canada Kevin or some other Vancouverite may want to double-check the address, but I'm 99% sure this is the place that used to be called "Computer Warehouse" five or six blocks West of the Superstore on Grandview Hwy. Two years ago they had a fairly good selection of older PC-clone stuff, and some random other office equipment from around the area, but at generally pretty high prices. I mainly visited them when I needed networking cables and parts on a Sunday afternoon :-) I also got some working MFM drives >from them, and numerous broken MFM drives! They had some moderately interesting stuff in their "museum" area, but generally just bits and pieces that had been ripped out; nothing resembling any sort of complete system. For a while, they did have a rather good selection of Apple II GS units and parts, judging by the burn-in on the CRT's they'd been used at a local video rental chain as point-of-sale terminals. -- Tim Shoppa Email: shoppa(a)trailing-edge.com Trailing Edge Technology WWW: http://www.trailing-edge.com/ 7328 Bradley Blvd Voice: 301-767-5917 Bethesda, MD, USA 20817 Fax: 301-767-5927

25 years, 11 months

Altair parts and the like

by RCini＠congressfinancial.com

Thanks for the 8T97 offer. My goal for this project would be to make for myself an 8080-based SBC using modern parts and having some sort of front panel. I have no illusions of reproducing an Altair or IMSAI. Just thinking about this a little...maybe I could take Claus Guiloi's Altair "emulator" code and connect a virtual terminal to it. I have a dot-matrix printer font and a teletype font...hmmm...this is more interesting. Rich -----Original Message----- From: Will Jennings [mailto:xds_sigma7@hotmail.com] Sent: Tuesday, May 23, 2000 10:37 AM To: classiccmp(a)classiccmp.org Subject: Altair parts and the like Hi, Well if whoever was building the thing really wants to use 8T97's, I have 15 of 'em... Let me know if you're interested. Will J ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

25 years, 11 months

good new/bad news on the VLC firmware

by xds_sigma7＠hotmail.com

OK, I tried to send this direct to Chuck, but the e-mail bounced... anyway, I have 7 D27210's, all Intel, new in the tubes... Ironically, I got them >from a former DEC engineer ;p If anyone needs some, let me know. Will J ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

25 years, 11 months

DEC stuff 11/73

by rigdonj＠intellistar.net

Will the guy that made me an offer on the 11/73 contact me again? I lost your address. E-mail me directly. Joe

25 years, 11 months

Altair parts and the like

by xds_sigma7＠hotmail.com

Hi, Well if whoever was building the thing really wants to use 8T97's, I have 15 of 'em... Let me know if you're interested. Will J ________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com

25 years, 11 months

OT: Show how old you are with printer/punch card control codes.

by mmcfadden＠cmh.edu

Punch card trivia Any character in column 6 made this card a continuation of the previous card. This only applies to Fortran program source cards not data cards. Also don't triple punch any columns, the card reader with usually produce a check error I don't remember the drum card programming codes, you could skip columns, force numeric, automatically insert zeros and periods. Line printer trivia Many printer control codes were very useful when trying to print pictures on the back side of green-bar. Output on line printers + in column 1 don't start a new line 0 in column 1 double space 1 in column 1 form feed We used to turn over the paper and attempt to print "pictures" after hours. Somewhere I still have a 9-track tape from 1975 that has a "beautiful" woman on it. I heard that IBM sequentially printed Christmas banners at a trade show by using 3 printers each with a different color ribbon, Red, Green, Black, and feeding the paper continuously through each printer in turn. Nostalgia or is it Altzhimers Mike

25 years, 11 months

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