Date: Tue, 08 Jan 2002 14:58:31 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: D J Hawkey Jr <hawkeyd@visi.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Oh my god, Google has a USENET archive going back to 1981! Message-ID: <3C3B7997.205E404A@mindspring.com> References: <20.21dd4868.296bb1c2_aol.com@ns.sol.net> <3C3A810A.C616A903_mindspring.com@ns.sol.net> <200201081104.g08B4i309583@sheol.localdomain> <200201082138.g08LcFS61637@apollo.backplane.com>
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Matthew Dillon wrote: > Ah yes. By the time I was ready to throw my PET away the hardware > inside was so hacked up I don't think anybody but me could boot the > thing. I had replaced the character generator ROM with a RAM and wired > in a wire select to an unused bank, which meant the screen was spaghetti > on power-up until i LOAD'd a copy of the character set. UGH. You didn't load the RAM from the ROM at power on?!? We had the "high resolution graphics" board in one machine; it's where I did my first ray tracing code, for an Optics class. Now *that* was a cool third party board, replacing the character generator output with bitmapped graphics, and un-overlapping the video memory by actually wiring in the chip select for more RAM. > I had the machine language monitor extension rom. 8-). Quick, what are "A0", "A2", and "A4", and what are their operands? What's the difference between "4C" and "6C"? 8-) 8-). > I had wired in an extra 16K of dynamic ram, giving me 48K > total (bank selected) (imagine piggy-backing a bank of 14 > or 16 pin DIPs on another bank and soldering each lead, > except for the select, to the one below). I paid the $18 (a tidy sum, in those days!) for the 100 pin edge connector from DigiKey, and expanded that way. For the bank select, I had a set of sockets to sit in the sockets between the RAM and the motherboard for the select. Mostly I just ran with the 32K, which was enough for almost anything you would ever want to do... > I had the NMI button hooked up, of course, and I brought > the TTL video lead for the monitor out to act as a poor > man's oscilliscope. The insides of that box was a > mess. Heh. The only ugly thing about mine today is the replacement power diodes are larger so they won't cook, and I replaced the Molex connector do that opening and closing the case didn't short the power supply... > These days traces or so tiny and chip leads are so close > together (not to mention the 6+ layer boards!) that hacking > a PC's hardware is pretty close to impossible. Not to mention incredibly uninteresting. When PCI went in, the "experimentor's cards" became too complicated, as well 8-(, so things aren't nearly as easy as they used to be, even back in the ISA days... > But it's funny... I never had a desire to hack up my C64's > or my Amiga's. I guess there enough fun things to do with > them that hardware hacking wasn't necessary. You never did the "Fat Agnes" surgery, or the "Spirit" memory board thing on an Amiga 1000, so you could see the "double half bright" demo animation of the tap-dancing guy while "In the Hall of the Mountain King" played out the speakers? There's also the 68010 hack for the 1000 (you needed to hack virus code to make the MPSW fixup patch live across a reboot so that you could run the PC and Mac emulators, but it let you run SVR3.2 on the A1000, if you had the Supra SCSI drive and Zorro controller... ah, the first UNIX box I ever owned...). -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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