test-drb June 2008

test-drb@ccmp.vtda.org

194 participants
304 discussions

powering up older machines - is it safe?

by eric＠brouhaha.com

Brian wrote: > If that's the smoke he smelled, he wouldn't care about the other > machines. He'd be off looking for munchies... "Now where were > those chips?" Mmmmm... NMOS chips... With just a hint of boron...

16 years, 6 months

C <-> ASM translation problem

by lehmann＠ans-netz.de

Hi, As I promissed here comes my first question ;) While writing several C files for the WEGA/ZEUS kernel out of the disassembled objects (with unresolved symbols marked as external) I came across a piece of code I can't get to reproduce when compiling C. The original object contains: 0006de: 35a2 0004 ldl rr2,rr10(#$0004) 0006e2: 9424 ldl rr4,rr2 0006e4: 0704 7f00 and r4,#$7f00 0006e8: 5d04 8000 0004 ldl $8000+$0x4,rr4 I tried to reproduce it: ipc.ip_addr.l = *(unsigned long)(uap->addr.l)&0x7F00FFFF; Which generates: 0008 35a2 0004 59 ldl rr2,rr10(#4) 000c 0702 7f00 60 and r2,#32512 0010 5d02 8000* 61 ldl _ipc+4,rr2 0014 0004* which looks for me functional the same... I also tried: ipc.ip_addr.l = *(unsigned long *)(uap->addr.l)&0x7F00FFFF; Which generates: 0010 35a2 0004 60 ldl rr2,rr10(#4) 0014 1424 61 ldl rr4, at rr2 0016 0704 7f00 62 and r4,#32512 001a 5d04 8000* 63 ldl _ipc+4,rr4 Which looks "better" but isn't the same as the original because the adress of rr2 gets loaded into rr4 first, not rr2 itself. I'm a bit lost because I tried several different */&-pointer stuff to get this as it is in the original object without success. the elements ip_addr and addr are both of type saddr_t which is declare as follows: typedef union { caddr_t l; struct { unsigned left; unsigned right; } half; } saddr_t; /* segmented address with parts */ rr4 itself gets later overwritten in both codes - my code and the original object - it is not reserved for an internal C-variable. Maybe someone from you can help me here? -- Oliver Lehmann http://www.pofo.de/ http://wishlist.ans-netz.de/

16 years, 6 months

[personal] UK Computer Museum on TV

by roger.holmes＠microspot.co.uk

> From: "Mike Hatch" <mike at brickfieldspark.org> > > Have past experience with Elliott 803b, Digital PDP7 & 11/20, > Scientific > Data Systems SDS9300, ASR/KSR 33 & 35, Ampex TM4 tape drives. May I ask what machine the Ampex TM4 tape drives were connected to? I have them on my ICT 1301s, and I have a slightly different deck marked TM4 Leo but if you know of any other machines which used them it would be interesting. Do you know if they were always ten track read/write heads or were they different configurations? I guess the formats were different across different machines, it seems unlikely anyone else would have chosen to use 4 data bits and 6 CRC bits, and certainly not in multiples of 12 digits with the digits from each half of the word interspersed ending at a word of hex FFFFFFFFFFFF. Roger

16 years, 6 months

Australian Computer Museum

by jules.richardson99＠gmail.com

Does anyone know the fate of the Australian Computer Museum? Looking at their website at http://www.acms.org.au it looks like they were in real trouble a couple of months back. Does anyone know if they found alternative storage space for the collection (and therefore that the website just hasn't been updated)? cheers Jules

16 years, 6 months

Venner Electronics Modules

by thrashbarg＠kaput.homeunix.org

Hi, I've got here some electronic modules made by Venner Electronics LTD, Kingston By-Pass, New Malden, Surrey. One is a Transistor Decade Unit type TS.10/5 and the other just has Type TS 11/HF on it, where 11/HF is scratched into the metal label. Opening one reveals a number of Mullard OC44 Ge transistors. What on earth are they for? I can imagine they're for some sort of digital machine or even a whole computer, but I can't find any information about them or the company. Thanks, Alexis.

16 years, 6 months

Reconstructing Fastback Plus Backups from floppies

by johnwatson97＠optusnet.com.au

Hi Gary, I saw your 12 Mar 2007 post about reconstructing Fastback files. I have EXACTLY the same problem ! Did you get a solution ? Regards, John Watson.

16 years, 6 months

is this a terminal multiplexer?

by legalize＠xmission.com

See ebay item # 120269073061 We've talked about terminal multiplexers here before, as opposed to terminal servers. They sound like interesting devices to me and I was wondering if this item on ebay is one of those muxes or some kind of telecom equipment instead (its listed under telecom, but ebay items are often listed under the wrong category). -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

16 years, 6 months

classic computer/game machine color video generation

by chd_1＠nktelco.net

How is the color video for display on a TV generated? I have a reasonable understanding of how the composite video signal works, although probably not all the details. Each horizontal scan line consists of a lower frequency signal that represents the brightness with higher voltage being darker. Added to this is a higher frequency signal that represents color and the color is determined not by amplitude, but by phase shift relative to a reference generated during the horizontal retrace time. So, if this is how the video signal works, then to generate 16 colors, we could use one bit for a brightness level and 3 bits to select a color. I can see a D F/F to hold the brightness level during a pixel time.For color, I see an 8 bit shift register with the color signal being shifted though and an 8 to 1 multiplexer to select the phase based on the 3 color bits during each pixel time. Now add some resistors to set the right levels and maybe some capacitors to take off the sharp edges and you have a video signal. I know this is ignoring the sync signals. I am really interested in how you get color. OK, so how close am I? -chuck

16 years, 6 months

N8VEM homebrew SBC PCBs

by lynchaj＠yahoo.com

Hi All, I did finally finish my homebrew SBC PCBs and made an order for several. The manufacturer says they should arrive about 5 Jun 2008 or so. If anyone is interested in building their own, please let me know. The details about the SBC are at: http://groups.google.com/group/n8vem/web/n8vem-single-board-computer-home-pa ge http://groups.google.com/group/n8vem Thanks! Andrew Lynch

16 years, 6 months

Trying again, wanted: volker-craig terminals

by dgahling＠hotmail.com

I'm trying this again, since I still haven't gotten one, I'm looking for a volker-craig terminal, preferably an 4404 (not a 3000-series). I used these at western and would love to have one. If anyone has one they want to get rid of, sell, trade, etc, please let me know. Thanks, Dan. _________________________________________________________________ If you like crossword puzzles, then you'll love Flexicon, a game which combines four overlapping crossword puzzles into one! http://g.msn.ca/ca55/208

16 years, 6 months

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test-drb June 2008