Date: Mon, 7 Jan 2002 13:28:20 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: hackers@freebsd.org Subject: Oh my god, Google has a USENET archive going back to 1981! Message-ID: <200201072128.g07LSK655245@apollo.backplane.com>
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Oh my god. I don't even *remember* writing this one! This was when
I was 18. Google's archive isn't complete but they've done an incredible
job getting as much as they have.
Pet, C64, DMail, Shell (for the amiga), backup/restore utilities,
dme, dterm, AmigaUUCP, DICE, etc. It's all there in bits and pieces,
complete with my trademark spelling errors.
-Matt
:Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
:Posting-Version: version B 2.10.2 9/18/84; site ucbvax.ARPA
:From: dillon@ucbvax.ARPA (The Sherif "Matt D.")
:Newsgroups: net.micro.cbm
:Subject: Misc. Discussion 1541/2031/4040/2040
:Message-ID: <3957@ucbvax.ARPA>
:Date: Sat, 29-Dec-84 16:29:38 EST
:Article-I.D.: ucbvax.3957
:Posted: Sat Dec 29 16:29:38 1984
:Date-Received: Sat, 29-Dec-84 20:04:09 EST
:Distribution: net
:Organization: University of California at Berkeley
:Lines: 73
:
:
:
:Let me tell you a story about these drives. The first, the 2040, is a
:duel drive whos age is beyond counting. At one point commodore decided
:that the 2040 format was creating errors (It had one extra sector on
:several tracks). So, they modified the format slightly by taking out that
:sector. That is why the OLD 2040 has more storage than the NEW 1541/2031/
:4040. Now, Commodore tells us that the 1541, 2031, and 4040 have the same
:disk format. Bryce pointed out to me one day as we were muling over the
:hundreds of errors (not to mention the bad programming style) of the 1541
:DOS, that the 4040 uses a different spacing between sectors. Oh JUST GREAT...
:I suggest that to keep read errors at a minimum, you not write on a disk
:using a 1541 that was formatted on a 4040.
:
:Guess what! Commodore did not write a new DOS for the 1541 or the 2031.
:In fact, the used the 4040's DOS and attempted to take out all the references
:to the second drive. Well, they just didn't get them all and that is why
:you get that DRIVE NOT READY error sometimes. Their @replace bug was a
:classic, and that was one of the first thing Bryce fixed in his 1541 FLASH.
:
:But the story does not end there. Word has it that two people worked on
:the original DOS for the 1541/2031/4040/2040. One wrote the drive interface,
:and one wrote the communications protocal. Word also has it that the two
:hardly confered with each other at all... Hence the slowness of drive.
:
:You have to be an expert on 6502 to be able to understand the drive's DOS,
:considering how lousy the guy programmed it. Why commodore used a modem-
:speed interface with an intelligent disk drive I could not guess.
:
:I myself am a PET person. The best transfer speed I've been able to come
:up with a PET & 2031 has been 53KBytes/sec ... With sector loading, I've
:been able to get a skew factor of 3 and a 130 block load in 6.5 sec. Bryce
:has been able to turn the rinky-dink serial interface into exactly the same
:speed... Were both stuck on the skew factor. I think that's pretty good
:considering the controller Commodore used for the disk (It consists of a
:micro-processor, 2K RAM, 16K ROM, and 2 6522's. None of these, by the way,
:are dedicated as a floppy controller).
:
:And now we come to the (quote unquote) Build in RS-232C. The C64 does it all
:in software, and the outputs are +5/GND rather than standard -12/12V. Baud
:rates below 2400 work fine. Anything after that will not work well unless
:you do it by hand. Commodore has this nack of putting everything on the
:interrupt, you see; They put the disk-controller of the 1541... on the
:interrupt. I'm not kidding, to request a sector you wrote some crap into
:some memory and had to wait for a timer interupt to occur before the
:interrupt service routine would catch it and get/write the sector. In
:anycase, I'm getting off the subject; Commodore has the modem on the
:interrupt. So as long as you don't use the disk drive or printer, you
:can use the modem. You can either recieve or transmit (but not both at
:the same time). In other words, commodore blew it again in terms of the
:C64.
:
:
:You might ask if there is anything good about the commodore 64. Well, the
:graphics are good and the sound is fantastic. Don't let anyone tell you
:the sound is the pits... I've heard very un-computer like voice synthesis
:using only that single solitary SID. The graphics are good, considering
:that the C64 is only a small home computer. I particulary like the raster
:interrupt which makes it all worth while. You probably have heard that at
:any time the graphics chip can take 40cc from the processor. Well, using
:the raster interrupt, Bryce was able to sync the two and to a VERY FAST
:trasfer over the original serial lines sync'd with the drive to within
:3cc (On my PET, I used to use a single sync signal to sync the block transfers,
:Giving me a 32KByte/sec ifc with 8cc tolerances. Bryce suggested a double
:sync to sync the sync, so to speak, which is why I can do 56KBytes/sec over
:IEEE and he can do 20KBytes/sec over the original lines. With 1541 FLASH,
:the thoretical maximum is about the same as my IEEE transfers. In either
:case the transfer is 1000% better than Commodores, and the only holding
:factor is that the data must be read off disk before it can be sent over).
:
:
: Matthew Dillon (dillon@vax.Berkeley.ARPA)
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