test-drb July 2007

test-drb@ccmp.vtda.org

189 participants
323 discussions

Tandy 2000 hack

by chrism3667＠yahoo.com

any thoughts? And although he claimed the 2000 never generated a NMI, won't a parity error always do this? Irrelevant maybe cuz that's a catastrophic fault thing, not something typically encountered... Maybe he provided more details, but I'm tired... > > I was working on a mod, never completed, for the T2K > > that would make it > > after the O/S was loaded, 100% PC-compatible. > > Required 1 hardware chip, > > and a customized IO.SYS. Whereupon any DOS > > application would run on the T2K, > > even stuff doing serial-port manipulation, direct > > video-memory writes, DMA, > > etc. The one-chip mod was a PAL that monitored the address lines from the CPU, when It saw an I/O instruction in 'low' address-space, it generated an NMI (not used at all by the T2K), then the software service routine for NMI unwound the stack to find the offending I/O instruction, and re-mapped the "PC" functionality to the T2K hardware. Coupled with a timer-tick 'refresh' routine that copied data from "PC video memory" to the T2K video memory (remapping attributes, etc. as required.) The chip actually had 2 modes of operation -- NMI active, as described above, and 'NMI inactive', where it pretty much did nothing -- except listen for the 'magic words' that made it go active, that is. :) This enable/disable mode switching was necessary, to allow "T2K DOS" internals (and/or the 'sofware service routine) to access the T2K hardware directly. ____________________________________________________________________________________ Moody friends. Drama queens. Your life? Nope! - their life, your story. Play Sims Stories at Yahoo! Games. http://sims.yahoo.com/

16 years, 5 months

(no subject)

by compoobah＠valleyimplants.com

> At 09:46 AM 7/1/2007, Scott Quinn wrote: >> For a brief period, NewTek did have a Macintosh clone with a 68030 >> and system software that was a hybrid of System 6 and System 7, > > "NewTek" was an Amiga company, "NewTech" was the Mac clone company. > > - John Hmm-the reviewer in the magazine I have must have had spell-check on, as it came out "NewTek Duet" every time. Explains why I couldn't find much else on it.

16 years, 5 months

S-100 and other items looking for a new home

by w6nct＠arrl.net

Greetings, I am new to this group, so I hope that I am doing this correctly. I have a bunch of computer parts looking for a new home, many are from vintage computers. Most of the initial things I have posted are S-100 PCBs (memory, I/O, interfaces,...), many of which include documentation, and some even include software. I also have a NorthStar Horizon chassis (including linear P/S, motherboard, but no top cover or drives). There are other items as well, including a VME chassis; and I expect to have several Heathkit items posted soon. Unless specified, I believe that all of these items were operational prior to being boxed (several years ago), and still appear to be in good condition. I am enquiring with several people I have found on the Web, hoping to find one or more interested parties. I have considered posting them on eBay; but thought that I'd offer them directly first. These items are located in Southern California; so shipping outside that area may be a (minor) concern (for larger or heavier items). At the very minimum, I am interested in recovering the cost for S/H; but would prefer to get a bit more to help with my purchasing a new laptop. I have set up a temporary Yahoo Group to help with showing and describing the items; that way, it won't impact the bandwidth of sites such as this one. The Group is called "Verns_Stuff" (http://groups.yahoo.com/group/Verns_Stuff). If you have any interest in S-100, VME, or Heathkit computer items, please drop by. If you are not interested, but you are aware of other individuals or groups that might be, please feel free to forward this information on to them. Thank-you. Vern.

16 years, 5 months

What are the really unusual or weird computers?

by roger.holmes＠microspot.co.uk

> > From: "Mike Hatch" <mike.hatch at mclennan.co.uk> > >> Its got Ampex >> TM4 mag tape drives (not industry standard 7 or 9 track, these are >> ten track units with hubs the same design as professional audio >> tapes >> and the 2 and 3 inch wide video tapes once used by TV broadcasters). > > Our SDS9300 had TM4 drives but I don't remember them being 2 and 3 > inch > wide, I thought they were 0.5 inch, but then that was 35years ago. Yes they are half inch. What I meant was that they are not 'industry standard' half inch tape with large expanding hubs with the write protect ring in a groove in the reel. Instead the centres are much smaller, allowing 3200 feet on the same outside diameter spool as a 2400 foot reel using the same thickness tape (not the ultra thin tape). The reels are aluminium, not plastic, their centres have three notches which three matching 'fingers' within the hub fit into, holding the reel onto the hub. Some TM4s were fitted with small expanding hubs (the ones on the Leo and maybe others), but this did not fit 'industry standard' reels. The same design of hub is used on tapes of quarter inch, half inch, one inch, two inch and three inch, maybe other sizes too. I do not mean domestic quarter inch tape recorders, these use a simple nut on a stud. The write protect ring protrudes from the back of the reel, and three projections on the ring fit into three holes in the reel. The tapes themselves have a metalised leader which is electrically sensed by the deck. They also have a reflective early end of tape marker like later tapes, and I think they have a metalised leader at the end of tape, though I've never unreeled 3200 feet of tape to find out.

16 years, 5 months

Fwd: [acug0447] Fwd: Jim Butterfield passes away

by aliensrcooluk＠yahoo.co.uk

FYI: Regards, Andrew B aliensrcooluk at yahoo.co.uk rbernardo(at)iglou.com wrote: To: acug0447 at yahoogroups.com,auscbm at yahoogroups.com From: <rbernardo at iglou.com> Date: Sat, 30 Jun 2007 19:53:12 -0400 Subject: [acug0447] Fwd: Jim Butterfield passes away --- Forwarded message --- I regret to advise the Commodore community that Jim Butterfield has passed away. Jim died at 1:30 AM on June 29 after battling cancer which infected many parts of his body. His family advises that there will not be a funeral as such but a commemoration of Jim's life is planned in the next month or two. At the moment that is all the detail that I have to report. We have all lost a truly wonderful friend and teacher. Ernie Chorny Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/acug0447/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/acug0447/join (Yahoo! ID required) <*> To change settings via email: mailto:acug0447-digest at yahoogroups.com mailto:acug0447-fullfeatured at yahoogroups.com <*> To unsubscribe from this group, send an email to: acug0447-unsubscribe at yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/

16 years, 5 months

Drum vs. Core

by ajp166＠bellatlantic.net

> >Subject: Re: Drum vs. Core > From: "Chuck Guzis" <cclist at sydex.com> > Date: Fri, 29 Jun 2007 13:49:22 -0700 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >While the main store on the IBM 650, didn't most of the installed >base (eventually) also have 50 words of core as sort of a >"scratchpad" memory? > >Cheers, >Chuck This was common. The problem with rotating memory, mercury delay, magnostrictive delay and even shift registers is they are not random access they are sequential access They all have a fixed delay and you wait for what you want to "come around". Programmers had to program around that if speed was required. Allison

16 years, 5 months

Semi-OT: Interesting or unusual PC Compatibles?

by compoobah＠valleyimplants.com

> Now, of course, such an effort would be in violation of DMCA, but it > worked back then. I'm surprised that no one did that with the Mac > ROMs--anyone know why not? Probably because they would also then need to clone the system software as well, a much bigger task for a much smaller (potential) market. Apple would have been much less likely to deal with clone makers than Microsoft was. While the system software was made freely available in the early years, it is unlikely it would have stayed that way if clone makers had been successful. For a brief period, NewTek did have a Macintosh clone with a 68030 and system software that was a hybrid of System 6 and System 7, with a user interface based on Motif. It suffered the same problems as the 1st - gen IBM clones as far as compatibility.

16 years, 5 months

Rare Commodore 8296 on EBay?!?!?

by gmanuel＠gmconsulting.net

Is this really as rare as he thinks it is? http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=130128193985&ssPageName=M ERC_VI_RCRX_Pr3_PcY_BID_Stores_IT&refitem=130128166016&itemcount=3&refwidget loc=active_view_item&usedrule1=CrossSell_LogicX&refwidgettype=cross_promot_w idget Greg

16 years, 5 months

Drum vs. Core

by cc＠corti-net.de

On Fri, 29 Jun 2007, Brent Hilpert wrote: > Indeed, according to http://www.columbia.edu/acis/history/650.html there was > 60 words of core used as a buffer between the drum and tape drives to account > for their different data rates, but which could also be used for other stuff. Well, then you have to count the LGP-30 as computer with core memory, too, because the interface to the (apparently extremly rare) magnetic tape drives (yes, there were tape drives for the LGP-30!) contained core memory as buffer. The drive would buffer the block in core so that the LGP-30 could read it with its own speed (and vice versa). Christian

16 years, 5 months

stuff on ebay

by dgriffi＠cs.csubak.edu

Now that I have some more time to do it, I've listed some stuff on Ebay. My name there is "frotz661". -- David Griffith dgriffi at cs.csubak.edu A: Because it fouls the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing in e-mail?

16 years, 5 months

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test-drb July 2007