test-drb April 1999

test-drb@ccmp.vtda.org

170 participants
1190 discussions

by cmcmanis＠mcmanis.com

Are a waste of time on separate architectures. We've basically seen the benchmark discussion recreated in what is a somewhat classic vein. If there were really old Usenet archives around you could search comp.sys.arch for the keyword Dhrystone and get this same conversation all over again. However, there are fun competitions, and I'll toss one out for y'all: Compute as many digits of pi as you can on a CARDIAC. Lowest score wins, points scored as follows: +1 for every memory location used. (0 and 99 don't count) +4 for every space on the output card that doesn't contain part of the answer. A card has 24 slots so submitting no program at all will score 96. --Chuck

25 years, 8 months

Amiga 2000HD Hard disk

by ethan_dicks＠yahoo.com

--- LordTyran <a2k(a)one.net> wrote: > Hello, a while ago I got a semi-functioning Amiga 2000HD... after > tinkering with it for a bit, the accelerator crashed the machine every few > minutes, the install was screwed, etc. So, After finding the 68k chip bad, > I pulled one from my dead A500 I can sell you another 68K chip, cheap. I have several. > ...I now how a functioning system... except the HD with a screwed > up install. I want to use a 105-meg SCSI drive that I rescued from a Mac > at school. I have an complete set of install disks for the 2.1 OS but for > some reason it can't detect my drive when I try to format it. None of the > hard disk programs detect it. (When I boot from the install disk with the > old HD installed, it appears as an icon on the Workbench, but when I boot > with my 105 meg drive installed, no other icons appear. There is a prep phase before which you will get no icons. Amigas use a thing called the RDB which contains, among other things, the partition table. Look for HDToolbox in (I think) the Tools drawer of one of the bootable OS2.1 floppies. You can low-level format the drive, check for bad blocks, add new blocks by number, test the surface (read only) and write out a partition table. OS2.1 might insist on a couple of partitions, WB_2.x and WORK. My old A3000 came with some interesting disks for Workbench 2.01 and 2.02; there's some extra stuff that is helpful for auto-partitioning disks with script files. You will want at least 15Mb for WB_2.x All it has to hold is the OS itself (5 880Kb floppies) and anything you add of that sort (drivers, fonts, etc). All the real stuff should go into WORK. Good Luck, -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

25 years, 8 months

x86, x86 everywhere, but... (was OT: Re: Time to declare State

by ethan_dicks＠yahoo.com

--- Tony Duell <ard(a)p850ug1.demon.co.uk> wrote: > > What? Valueless? Not at all. Get an XT or an 286, give it a 10 or 20 meg > > HD, throw a 10BaseT network card in it (I have those coming out of my > > ears, thanks to all my friends!), install Minix on it, and make it a node > > on your friendly house-hold network. Or forget the network card and use a > > Oh, sure. _I_ don't think they're valueless either. On the desk in front > of me is an XT (original IBM5160). It runs my EPROM programmer, my GAL > programmer, my cable tester, etc. It reads PERQ disks. It is certainly > useful to me. I use a Commodore Colt for the same thing - 8088, soft turbo mode, 3 8-bit slots, supports 3.5" 720K floppies, built-in XT-IDE (I've got a WD93028X on it). I have my ROM programmer on it, an 8003 Ethernet card and I move files to and from it with Kermit over TCP/IP. This does not mean that it's all I would ever want... I enjoy the web, and it's not suitable for more than Lynx, but I do use it and I wouldn't retire it easily. -ethan _________________________________________________________ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com

25 years, 8 months

Burroughs 205 anyone??? (fwd)

by siconic＠jasmine.psyber.com

Can anyone help this guy out? Please reply to the original sender. Reply-to: B9BUILDER(a)aol.com ---------- Forwarded message ---------- Date: Fri, 16 Apr 1999 23:37:53 EDT From: B9BUILDER(a)aol.com Subject: Help!!!! Hello My name is Doug Hines, I am trying to build a set from the tv show lost in space. I have been told by several people that the main flight deck had several burroughs 205 computers. I am trying to find someone that might have that model for sale. Any help would be super. Thank's. Doug Hines Sellam Alternate e-mail: dastar(a)verio.com ------------------------------------------------------------------------------- Puttin' the smack down on the man! Coming in 1999: Vintage Computer Festival 3.0! See http://www.vintage.org/vcf for details [Last web site update: 04/03/99]

25 years, 8 months

OT Was z80 timing... 6502 timing

by edick＠idcomm.com

I was trying to figure out whether it was politically correct to correct someone else's spelling in this forum. I had the impression that there was no orthographic police here. There certainly is a lot of error in that department. Even my rented fingers don't spell any worse than the average here. Now . . . What do you mean your money's on TONY? Which Tony? Dick -----Original Message----- From: jax <jax(a)tvec.net> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 10:49 AM Subject: Re: OT Was z80 timing... 6502 timing > >>Ooh! A machine code competition. I'm in! I'll do the 6502 and whoop >>EVERYONE'S ass! >> > > >Wait just a minute..... > >Since we have been discussing various "ethnic" pronunciations, I am >compelled to point out that this statement may be interpeted differently >than intended. > >As a born\bred survivor of the land of redneck, pickup truck, and chewing >tobacco, I assert that a "whoop" is a loud yelling type of activity. The >execution of which on someone's posterior will bring a certain confusion to >your enemy ( he will think you are a fruit ), but will not render him >defeated. > >I laughed so hard at this mental image it made me hurt. :) > >Try "whup" next time, as in "opening a can of whup-ass". > >My 2 centavos from the Republic of Texas. > >BTW, my money's on Tony. > > > jax(a)tvec.net >

25 years, 8 months

unsubscribing/resubscribing

by roblwill＠usaor.net

Can someone please tell me how to unsubscribe/resubscribe? I currently have a dedicated classiccmp email address, and would like to switch the list over to it, but I forget how. ThAnX, -- -Jason Willgruber (roblwill(a)usaor.net) ICQ#: 1730318 <http://members.tripod.com/general_1>

25 years, 8 months

FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive)

by mark_k＠iname.com

On 10 Apr 1999 Richard Erlacher wrote: >YES! and that's exactly why the pulse overlap was correctable with >write-precompensation at least in hard disks at 10x the data rate. In >general the amplitude of the pulses was sufficient to be detected by the >usual circuitry, but because the timing was quite far off due to the peak >shift introduced by the summing effect of the head/media combination. >Precompensation, which was not needed for FM, was between 188 and 125 nsec, >depending on the drives in use. On the older drives, 188 was pretty common. >The "bit-shift" was mitigated somewhat by the reduction of write-current on >the inner tracks. Can someone explain exactly what precompensation is? I remember reading about this in the Amiga hardware manual; in the ADKCON register there are two bits which set the precompensation (none, 140ns, 280ns or 560ns), and also one that selects GCR precompensation or MFM precompensation. Note that the encoding method is implemented completely in software, so you are not limited to MFM and GCR. (There's also a control to set the data rate, 2us or 4us per bit cell. 2us is used for MFM, apparently for GCR 4us is necessary.) -- Mark

25 years, 8 months

z80 timing... 6502 timing

by allisonp＠world.std.com

<What were the Z80 instructions? I'd like to test them on a SBC and documen <them for the future. <Thanks, <-Dave Found this on my disk. Allison ***************************************************************** Undocumented Z80 Instructions (apply only to Z80) The Z80 IX/IY operators are missing (byte ops) mnemonic: IN ,(C) OP code: 0EDh,070h Description: Same as IN A,(C) except the A register isn't changed (flags are set as if it was changed). NOTES: This instruction can be used to test and discard the value of a port without destroying any registers. mnemonic: SLAS B OP code: 0CBh,030h Description: Shift Left Arithmetic Special B. Same as SLA B except bit 0 of B is set instead of cleared. mnemonic: SLAS C OP code: 0CBh,031h Description: Shift Left Arithmetic Special C. Same as SLA C except bit 0 of C is set instead of cleared. mnemonic: SLAS D OP code: 0CBh,032h Description: Shift Left Arithmetic Special D. Same as SLA D except bit 0 of D is set instead of cleared. mnemonic: SLAS E OP code: 0CBh,033h Description: Shift Left Arithmetic Special E. Same as SLA E except bit 0 of E is set instead of cleared. mnemonic: SLAS H OP code: 0CBh,034h Description: Shift Left Arithmetic Special H. Same as SLA H except bit 0 of H is set instead of cleared. mnemonic: SLAS L OP code: 0CBh,035h Description: Shift Left Arithmetic Special L. Same as SLA L except bit 0 of L is set instead of cleared. mnemonic: SLAS (HL) OP code: 0CBh,036h Description: Shift Left Arithmetic Special (HL). Same as SLA (HL) except bit 0 of (HL) is set instead of cleared. mnemonic: SLAS A OP code: 0CBh,037h Description: Shift Left Arithmetic Special A. Same as SLA A except bit 0 of A is set instead of cleared. *****************************************************************

25 years, 8 months

FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive)

by edick＠idcomm.com

Yes, . . . at least I think I can. When data is written to magnetic media, there is a maximal bit density which can be written which is a function of the head and media characteristics as well as the velocity with which the data stream passes the heads. each transition is detected (read) as a pulse of a given width and amplitude. Changes in the sense of the data are recorded by reversing the magnetic flux written on the medium. If two flux reversals are written close together, they can overlap slightly. The consequence of this overlap is that their peaks are effectively pushed apart by the summing of the adjacent flux reversals, since the two amplitudes are never zero but are simply reversed while still having a non-negative value. The pulses resulting from the recovery of these reversals in flux are added together. Since they overlap, the insignificant portion close to the crossover are nonzero, so in the sum, the rising waveform of the second pulse is subtractively combined with the falling waveform of the first. This means that neither pulse reaches its maximum amplitude but its apparent peak appears at the point on the rising waveform at which the difference between the two pulses is reached, which makes the first pulse peak earlier and the second pulse peak later. In order to compensate for this, the pulse which would logically be detected "too early" is written late, and the pulse which would be detected late is written early, and as a result, the resulting pulse train is slightly reduced in amplitude, but the peaks are detected at the proper times, which is what matters. Dick -----Original Message----- From: Mark <mark_k(a)iname.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Saturday, April 17, 1999 3:20 PM Subject: Re: FM, MFM, and GCR channel codes (was Re: stepping machanism of Apple Disk ][ drive) >On 10 Apr 1999 Richard Erlacher wrote: >>YES! and that's exactly why the pulse overlap was correctable with >>write-precompensation at least in hard disks at 10x the data rate. In >>general the amplitude of the pulses was sufficient to be detected by the >>usual circuitry, but because the timing was quite far off due to the peak >>shift introduced by the summing effect of the head/media combination. >>Precompensation, which was not needed for FM, was between 188 and 125 nsec, >>depending on the drives in use. On the older drives, 188 was pretty common. >>The "bit-shift" was mitigated somewhat by the reduction of write-current on >>the inner tracks. > >Can someone explain exactly what precompensation is? > >I remember reading about this in the Amiga hardware manual; in the ADKCON >register there are two bits which set the precompensation (none, 140ns, 280ns >or 560ns), and also one that selects GCR precompensation or MFM >precompensation. Note that the encoding method is implemented completely in >software, so you are not limited to MFM and GCR. > >(There's also a control to set the data rate, 2us or 4us per bit cell. 2us is >used for MFM, apparently for GCR 4us is necessary.) > > > >-- Mark >

25 years, 8 months

z80 timing... 6502 timing

by allisonp＠world.std.com

The 6502 series ahd all sorts of undocumented opcodes and they tended to change with later versions. <THe 65xx stuff is quite known, but what has been new to my ears are the <8085 'hidden' operations. Those were more useful as the 8085 had some rather open holes in the instruction set. The z80 also had a raft of them all commonly supported though officially unofficial. and none were compatable with the 8085 hidden ops (in either direction). Allison

25 years, 8 months

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test-drb April 1999