[cctalk] Re: Qume 842 8" Disk Drive Question
The drive works perfectly for double sided disks (using the appropriate index hole). Yea, 8" drives are a bit funny like that. You know this, because context. Some future google-ologist might not. So. 8" drives have a different index position for SS and DS. In your case I suspect either the emitter LED or the receiver phototransistor ro maybe the wiring or what ever conditioning on the PCB is b0rken for the SS sensor. Assuming of course your drive has two sensors -- I have not yet owned an 8" drive like that, the ones I have had were dedicated SS or DS. W
[cctalk] Re: VCF SoCal
I have found that computers are much like motorcycles: many of the most interesting were never available in the US. Computers are much like motorcycles: many of the most interesting ones were TERRIBLE! W
[cctalk] Re: Vmebus
Anyone have a VMEbus system they use at least occasionally? If so, what make/model/config? I still use a couple of PPC VME boards (DY4 / Curtiss Wright 182/183/184, both Conduction-Cooled and Air-Cooled) to test the tail end of hardware that we are still shipping (by now EOL and basically NOS). But it's work, I don't find them interesting. If someone here has the warm fuzzies for PPC VME, we can talk :-) W
[cctalk] Re: Computhink Eagle 32 - software, docs, info?
Hi all Oops that went off before I was finished with it. I suspect that I can figure out from the pattern of I/O accesses which devices are at which address in the memory map, at least if I bring up an emulation in MAME. That should at least allow writing new code for it, and _maybe_ even figuring out which CRT controller the video hardware uses and where in the memory map it is. (I suspect the 6845 and/or 6847 just from the time period, but who knows? Gotta see what it actually do when trying to show the âIPL IN PROGRESSâ string contained in the ROM, or one of the couple error strings ) As far as I can tell this is where a character gets displayed. ; character in +1(A6) 00FFCE0C : 48E7 C000MOVEM.L D0,D1,-(A7) 00FFCE10 : 302B 06ACMOVE.W +1708(A3),D0 ; get something 00FFCE14 : 6122 BSR $00FFCE38 ; do something 00FFCE16 : 0040 8000ORI.W#$8000,D0 00FFCE1A : 11C0 8001MOVE.B D0,$00FF8001 ; Low byte 00FFCE1E : E048 LSR.W#8,D0 00FFCE20 : 11C0 8003MOVE.B D0,$00FF8003 ; High byte 00FFCE24 : 11EE 0001 8005 MOVE.B +1(A6),$00FF8005 ; Character 00FFCE2A : 0838 0006 801B BTST #6,$00FF801B ; Wait for a flag 00FFCE30 : 66F8 BNE $00FFCE2A 00FFCE32 : 4CDF 0003MOVEM.L (A7)+,D0,D1 00FFCE36 : 4E75 RTS ; Here with something (from $06AC(A3)) in D0 ; current guess, it's the cursor position, which then gets translated ; to an X and a Y byte in D0.w 00FFCE38 : 0C2B 0050 06B7 CMPI.B #$50,+1719(A3) 00FFCE3E : 6628 BNE $00FFCE68 ; Return 00FFCE40 : 48C0 EXT.LD0 00FFCE42 : 81FC 0050DIVS #$0050,D0 00FFCE46 : 4840 SWAP D0 00FFCE48 : 3200 MOVE.W D0,D1 00FFCE4A : 4840 SWAP D0 00FFCE4C : ED48 LSL.W#6,D0 00FFCE4E : 0C01 0040CMPI.B #$40,D1 00FFCE52 : 6C08 BGE $00FFCE5C 00FFCE54 : 11FC 8013 MOVE.B #$00,$00FF8013 00FFCE5A : 600A BRA $00FFCE66 00FFCE5C : 0441 0040SUBI.W #$0040,D1 00FFCE60 : 11FC 0001 8013 MOVE.B #$01,$00FF8013 00FFCE66 : 8041 OR.W D1,D0 00FFCE68 : 4E75 RTS Or maybe it's talking to a chip (not 6845 which is memory mapped or 7220 which has two registers only) and someone recognises it? W
[cctalk] Re: Computhink Eagle 32 - software, docs, info?
Hi all Chris gave me a copy of the boot ROM and I played around with it a bit. I threw the 4KB of boot ROM in Ghidra and confirmed a couple things: - At boot, ROM is mapped to 0, and then remapped either by a write to the location or by a cycle counter: The initial stack pointer at 0x0 is 0x0001fffe and the initial program counter at 0x4 is 0x00ffc026, indicating the ROM is normally located at 0x00ffc000. - The ROM freely interchanges addresses in the 0x00ffc000..0x00ff range and addresses in the 0xc000..0x range, which is annoying to deal with in Ghidra. The code takes advantage of the 68000 sign-extend on absolute short addressing mode, like move.b #$00, $8011. IDA correctly disassembles this to "move.b #0,($FF8011).w". I assume Ghidra if sign-extending it all the way to 8011? - I/O devices appear to be in the 0x00ff8000..0x00ffbfff range, all of the devices accessed via the bootstrap seem to be barely above 0x00ff8000. - Only NMI, bus error, interrupt 2, and interrupt 5 are set up by the bootstrap. Yup. - The bootstrap is very bare-bones but still has a bunch of indirection in it; itâs obviously written in assembly, but it does seem to have parameterization so it may support both console and serial I/O. I suspect either some low-level high-level language, or massive use of macros (which is in effect a low-level high-level language :-) Code like: ; Called with A6 pointing to a length and a string address 00FFCA4C : 48E7 8080MOVEM.L D0,A0,-(A7) 00FFCA50 : 3016 MOVE.W (A6),D0 ; length 00FFCA52 : 48C0 EXT.LD0 00FFCA54 : 206E 0002MOVEA.L +2(A6),A0; pointer to string 00FFCA58 : 508E ADDQ.L #8,A6; clear stack 00FFCA5A : 5380 SUBQ.L #1,D0 00FFCA5C : 6B0E BMI $00FFCA6C; done 00FFCA5E : 518E SUBQ.L #8,A6; make space on stack again 00FFCA60 : 1D58 0001MOVE.B (A0)+,+1(A6) ; one character on stack 00FFCA64 : 4EB8 C566JSR $00FFC566 00FFCA68 : 51C8 FFF4DBF D0,$00FFCA5E ; loop 00FFCA6C : 4CDF 0101MOVEM.L (A7)+,D0,A0 00FFCA70 : 4E75 RTS I suspect that I can figure out from the pattern of I/O accesses which devices are at which address in the memory map, at least if I bring up an emulation in MAME. That should at least allow writing new code for it, and _maybe_ even figuring out which CRT controller the video hardware uses and where in the memory map it is. (I suspect the 6845 and/or 6847 just from the time period, but who knows? Gotta see what it actually do when trying to show the âIPL IN PROGRESSâ string contained in the ROM, or one of the couple error strings ) Chris
[cctalk] Re: Computhink Eagle 32 - software, docs, info?
Hi Chris and all - No video board, whether text or graphics Since thereâs no video board in the system, and a couple of cables internally that arenât attached to anything, I expect it was removed by a previous caretaker. This is sad because without one itâs unlikely to come up, not that anyone has found any software for it. On the other hand, there are zero PALs, so both full reverse engineering and maintenance should be straightforward. I've scanned the press releases and adverts that come up on Google and I'm going to wager it was meant to be used with one or two terminals. Nowhere do they mention a display, and the adverts show a box sitting next to a terminal. Send me a copy of the ROM binary please? W
[cctalk] Re: Microcom S-64 8085 system
Hi Tony and all It might have run CP/M (which will run on an 8080, and therefore on an 8085). That needs RAM at location [1]. I know of CP/M, I even used CP/M (on my Apple) but I did not know it needs RAM at . That's kind of strange, since everything that ran CP/M (OK, everything -80) has vectors at 0. I guess there was a reason behind it. I see the CPU board has a jumper "F000/F800" so I guess it does something to map that address to 0 after reset. W
[cctalk] Microcom S-64 8085 system
Hi all I re-discovered some eurocards I found in a box at a swapmeet long ago. It looks like a complete 8085 system. Lots of RAM, 2K EPROM, I/O, FDC. The strange thing is that the EPROM is mapped at F800, the code in there looks like 8085 code, and looks like it wants to live at F800. And there's RAM at . The DIN41612 A/C 64 pin bus has provision for 16 bits data. Pics here http://retro.co.za/8085/Microcom/ Anyone maybe have more information on this? I'm curious. W
[cctalk] Re: PT-68K
Hi all I get the digest so I lag. From: skogkatt...@yahoo.com It's a IBM PC form factor 68000 based project that was featured in Radio Electronics. Anyone remember it or even know what I'm talking about? It would be a fun prokect. Come on over to "List: " there are people still running those. Peter Stark passed away September last year. There's also Ingo Cyliax' 68030 box, also PC form-factor and ISA. W
[cctalk] UK members: Mushroom Components
Hi all I have before obtained obsolete 8-bit chips from Paul at mushroom.co.uk. But now my emails are not answered and their phone also doesn't seem to work. Does anyone know what happened and whether they're still around, or whether someone else took over their stock? Thanks W
Re: Mystery chip SCM44506L
Very likely a semi custom or custom memory device, due to the prefix. Armed with that and the fact that pin 1 connects to the leadframe I figured maybe it's something like the 6830 Mikbug prom -- 0V on 1, 5V on 12, data on the left, address on the right. Tried reading it like that (for all 16 combinations of chip selects) but 0xFF throughout. So I popped the lid, stuck it under a microscope. The chip says "MCM6816" which is in fact a 1k ROM. Anyone have more information on the 6816 ROM? Thanks W
Mystery chip SCM44506L
Hi all From a friend's estate I have a Motorola 24-pin 0.6" purple ceramic DIP. SCM44506L 7610 B Any idea what this can be? W
Re: Eudora email client source code released
For the last five years I've been working with Qualcomm and others to allow the Computer History Museum to release the source code of what was, in my opinion, the finest email client ever written: Eudora. It's finally done! Yay! Now someone can fix the bugs :-) (6.2 here. Massive archive of emails. The search function is superb). W
TRS-80 bits
Hi all I have a TRS-80 Model 2000 B/W Graphics board and a TRS-80 Card Cage kit (upgrade model 12 to model 16B) Are either of these worth shipping from the antipodes to anyone? W
Re: Oki 3305 disk drives
Hi all OK, following up on my own post here. I have a couple of Oki 3305BU 1/3 height 5 1/4" drives. On startup the motor spins and the heads load, but the heads don't move. Also, my BIOS tells me I have a drive failure. On taking them apart for a bit of a lube I noticed they have EPROM 8748s inside. Could this be the problem, EPROMs lost data? This would be a first for me, I have EPROMs from the seventies which are still fine. I caused (I have people working for me who are really good at this) the 8748 to be removed from the one PCB. Reading it in my Expro gives me sort-of random results. Looks like some bits are high, some are low, and some float all over the place. No two reads return the same data, but some bytes are constant over two or three reads and other bytes are constant over two or three other reads. Is this the way an EPROM would fail? Seems reasonable to me. Anyway, I guess I'm SOL unless I can find a working drive. As far as I can tell these were used in the Heath / Zenith 170/170 luggables, also in the Morrow Pivot maybe. Tony would probably just rewrite the firmware. It's only 1024 bytes, how hard can it be? :-) Seriously, I am thinking of reading each byte say 100 times, averaging that, and then sticking the whole thing through a disassembler. But it seems a bit of a mammoth task. W
Oki 3305 disk drives
Hi all I have a couple of Oki 3305BU 1/3 height 5 1/4" drives. On startup the motor spins and the heads load, but the heads don't move. Also, my BIOS tells me I have a drive failure. On taking them apart for a bit of a lube I noticed they have EPROM 8748s inside. Could this be the problem, EPROMs lost data? This would be a first for me, I have EPROMs from the seventies which are still fine. Anybody familiar with these drives? Thanks W
bode.ee.ualberta.ca
Hi all Does anyone have a mirror of bode.ee.ualberta.ca or know where I can find one? Sheesh the internet's supposed to be a repository but stuff is disappearing off of it like there's a black hole somewhere. W
Re: Odd disk image format... .552?
Recently found some long-lost images of 5 1/4" floppies that were sent to me... 10-15 years ago. Here's one of them: http://www.corestore.org/RP06.552 Looks like a straight image for a 1.44 what we call "stiffy". The 522 is the version of RP06. Google leads me to http://www.corestore.org/rp12.htm so you already know what it's for :-) W
Re: Multitech MicroProfessor
Possibly a long shot since I think the MPF was only a UK/Europe thing but At least one made it to South Africa. But no, I have neither the expansion board nor the manual I'm afraid. W
