test-drb January 2008

test-drb@ccmp.vtda.org

221 participants
430 discussions

by jwest＠classiccmp.org

I was contacted by someone with an NCR 3120 laptop (1990). They want to sell it for best offer plus shipping. It's located in arizona and from the pics looks to be minty. If anyone is interested, please contact me off-list. Jay

16 years, 11 months

Has anyone ever written a standalone Commodore disk drive emulator?

by ethan.dicks＠usap.gov

Hi, Commodore folks, I have just tracked down an ISA IEEE-488 card and was thinking that it might be interesting to use it to build an older PC into a Commodore diskette drive emulator - I recall there are various projects to interface modern hardware to PETs (like the C2N232 I have with me), but the idea in this case is to allow existing apps to work as if there were a real C= drive hanging off the PET's IEEE port. Essentially, the PC would act as closely to, say a 4040, as possible. My thought was that if I had a real IEEE-488 interface, it could handle the physical-layer protocol, and the emulator would only have to handle sending and receiving command strings and data. The virtual diskettes would be, of course, image files. I'm not really as worried about RELative files - more along the lines of "direct access" files where the code running on the PET wants to read and write individual sectors, ignoring the C= DOS filesystem. That is, in fact, the major reason for trying to emulate drives in the first place - if it was just a case of loading and saving streams of data as files, the C2N232 does a fine job of that (and costs on the order of $10 to breadboard). There seem to be a number of ways to emulate C= IEC-bus devices (such as the 1541-III), but not for the IEEE-488. If anyone can point me at any existing projects, even if they are incomplete, it would be a big help. Thanks, -ethan -- Ethan Dicks, A-333-S Current South Pole Weather at 30-Jan-2008 at 02:00 Z South Pole Station PSC 468 Box 400 Temp -34.8 F (-37.1 C) Windchill -57.9 F (-50.0 C) APO AP 96598 Wind 7.9 kts Grid 45 Barometer 674.7 mb (10829 ft) Ethan.Dicks at usap.gov http://penguincentral.com/penguincentral.html

16 years, 11 months

DG10 AOS tapes

by mnusa2＠hotmail.com

I have some DG10 AOS tapes which I can not use and do not need. I have not tested these tapes or contents. 8 pcs of 45 MB QIC-2 tapes. If any interest please email. _________________________________________________________________ Windows Vista + Windows Live. Astu digitaaliseen maailmaan. http://get.live.com

16 years, 11 months

Z80 Divide by 10

by cclist＠sydex.com

> Date: Tue, 29 Jan 2008 06:45:46 -0500 > From: M H Stein > >Some people get rather upset at the lack of symmetry, and lack of certain > >instructions that might be handy, such as a load immediate into segment > >registers. > And some people just get rather upset by _anything_ that doesn't match > their view of how the world "should" be... Sigh. As long as it's possible to "get there from here", I don't much mind how an instruction set's laid out. I'll learn it and learn to work around the problem areas, such as the lack of an inclusive-OR instruction on the CP1600, or the weird setup of the RCA COSMAC, or the asymnetry of <fill in the blank>'s instruction set, or the lack of a hardware stack on a PDP/8. If you want strange and asymnetric, try working with a few samples of the current crop of microcontrollers. You can get used to anything. In a way, this line of discussion reminds me of an Inuit criticizing the Tongan language for the lack in the vocabulary for different types of snow. You work with what you've got. Cheers, Chuck

16 years, 11 months

Fast 8Kx2 ROM replacement

by cclist＠sydex.com

> Date: Mon, 28 Jan 2008 14:49:18 -0500 (EST) > From: Jeff Jonas > Why not try for a free sample of the Freescale Magnetoresistive Random > Access Memory (MRAM): it's fast and needs no power at all. The largest > seems to be P/N PR2A16AVYS35 4MBIT I was also going to suggest the Ramtron FRAM, but was looking for something close to the OP's original target of 2Kx8. The smallest parallel-access FRAM that Ramtron offers is 8Kx8, which is why I didn't suggest it. Cheers, Chuck

16 years, 11 months

8-bit micro MMU's

by cclist＠sydex.com

> Date: Tue, 29 Jan 2008 01:19:35 -0500 > From: Dave McGuire > A slight diversion here...What is wretched about the 8202? I ask > because I got ahold of a few not long ago (and some 8203s) and was > considering putting something together with them to play with. As I recall, the timing, on chip-to-chip samples was all over the place making it a headache to design a manufacturable product. The second-generation 8203 is much better in that respect. I'd recommend that you skip the 8202. If it's a one-off and you have more than one sample, it may not matter. I thought it interesting that IBM avoided the problem of a DRAM controller altogether on the PC and dedicated a channel of the 8237 DMA controller to serve as refresh generator. You'dve thought that Intel would have made them a great deal on one. Cheers, Chuck

16 years, 11 months

a tad OT: creating a bootable cflash card

by chrism3667＠yahoo.com

I'm stumped. All I have to work with is a WinXP laptop that doesn't boot off anything special in particular. The CD drive yes, but that's about it. I once was able to make bootable CD's w/early versions of Norton, but I doubt that would work for a compact flash card. I had thought I could "format/s" inside a dos box...no dice. even the "format" option arrived at by right clicking doesn't allow you to create a bootable partition. apparently "fdisk" doesn't exist in XP. I don't even have my USB floppy drive handy. Not that I would imagine DOS 6.22 would recognize a PCMCIA slot. Is there a way of running an *alien* DOS within XP. In a DOS box in other words? No, I don't imagine so. Whenever you click on a foreign command.com, you get a "wrong version" message or something. No I don't have the WinXP embedded resource kit (there's a program called bootprep that allegedly might help). I'm not trying to work with XP, just utilize it to create a DOS-bootable device. help ____________________________________________________________________________________ Looking for last minute shopping deals? Find them fast with Yahoo! Search. http://tools.search.yahoo.com/newsearch/category.php?category=shopping

16 years, 11 months

Anybody ever find Kai Kaltenbach?

by tshoppa＠wmata.com

I was trading some stuff with Kai Kaltenbach back around 1996/1997 or so, and promised him a binder of docs when I found it. Well, I found the binder, and now I cannot track him down. Anybody have a current E-mail address for him?

16 years, 11 months

Z80 Divide by 10

by ajp166＠bellatlantic.net

> >Subject: Re: Z80 Divide by 10 > From: Sean Conner <spc at conman.org> > Date: Mon, 28 Jan 2008 19:35:52 -0500 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >It was thus said that the Great Jim Leonard once stated: >> >> I find it amazing that there's an instruction set even more annoying >> >> than >> >>the 8086 (segments and all). I was amazed at the lopsidedness of the >> >>instruction set. I'm beginning to think I was lucky in skipping this >> >>particular chip (my first 8-bit was the 6809, so I think I got spoiled). >> >> Other than the goofy segment layout, what did you find "annoying" about >> the 8086 instruction set? > > Me? I didn't find it all that odd (at least, once I realized it was >better to look at the opcode map in octal instead of hex), but I do recall >reading various rants against the x86 on USENET in the early to mid 90s. I >did *a lot* of 8086 programming in the late 80s/early 90s, and still like >revisiting it from time to time (well, assembly in general, not specifically >the 8086). > > -spc (Man, I think I'd prefer the 6502 over the Z80 any day, and I hate > the 6502 ... ) ;) Having programmed a lot of the 8bitters and a fair number of 16 bitters my favorites are: PDP11, z80, 8085 and 804x(and 805x) I happen to hate Zilog neumonics for z80 though as it hides the fact that thre are hole in the instruction set. It also took me a long time to to switch from octal to hex as octal made the instruction set clear rather than hiding the holes. But I'm used to them especially the 8085, z80 and 804x. Others I find interesting are 6502, 1802, 6809 and TI9900 but I have to pay atttention as they require a different programming approach than would z80 or for that fact PDP11. Not better or worse just different. My all time favorite is PDP-8. Likely the most minimal instruction set that does enough. It has all the lacks XYZ of most every cpu and you can still code effectively with it. Also after PDP-8 everything looks good. ;) The 1802 also falls in that catagory, odd little machine with not much there but functional programs that are fast for the CPU speed manage to happen. There are few micros that do decent math, ti9900 and 6809 are ok at it but none were designed to be a primary number cruncher. Most code math routines effectively enough and thats what counts. If theres a comment here each cpu has something going for it or PDP8, PDP-11, z80 and 6502 would not have been amoung the longest lived cpus going. Yet despite that I still loathe the 8088/6 and later as the worst 8080 enhancement with a bag on the side. Just my .02$ Allison

16 years, 11 months

8-bit micro MMU's

by ajp166＠bellatlantic.net

> >Subject: Re: 8-bit micro MMU's > From: Dave McGuire <mcguire at neurotica.com> > Date: Tue, 29 Jan 2008 01:19:35 -0500 > To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org> > >On Jan 28, 2008, at 3:02 PM, Chuck Guzis wrote: >> With the slow memory chips back then, making things work with the >> wretched 8202 DRAM controller was a real chore. I seem to recall >> that if you ran worst-case numbers, you could wind up with the >> requirement of a negative access time for the DRAM for a 5MHz 8085. >> Adding bank-mapping hardware in the address path didn't improve >> things any. > > A slight diversion here...What is wretched about the 8202? I ask >because I got ahold of a few not long ago (and some 8203s) and was >considering putting something together with them to play with. Nothing save for the 8202 was optimized for 16k drams and the 8080 cpu (at 2mhz!). It was the older part. if your going to do Dram larger than 64k that the 8203 is the part of choise and pretty decent though not fantastically fast. the latter was because early Dram didn't do cas/ before ras/ refresh and other tricks to interleve the refresh cycle and the early parts were slow. > I worked with the 8207 DRAM controller extensively on the Navier- >Stokes Supercomputer Project at Princeton in the mid-late 1980s...We >had lots of problems with the memory arrays at first, but they were >eventually all traced to power...both nasty spikes on Vdd and ground >bounce. Big arrays are tough in the power gridding and bypass. The 8207 was a more involved part to use. Allison > > -Dave > >-- >Dave McGuire >Port Charlotte, FL >

16 years, 11 months

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test-drb January 2008