Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: anton@mips.complang.tuwien.ac.at (Anton Ertl) Newsgroups: comp.arch Subject: Re: tiny COBOL, Article on new mainframe use Date: Sat, 31 Aug 2024 17:29:57 GMT Organization: Institut fuer Computersprachen, Technische Universitaet Wien Lines: 30 Message-ID: <2024Aug31.192957@mips.complang.tuwien.ac.at> References: <20240830183742.000065c5@yahoo.com> Injection-Date: Sat, 31 Aug 2024 19:47:23 +0200 (CEST) Injection-Info: dont-email.me; posting-host="e7de4592dd4336f72b334ab25ad14682"; logging-data="1147381"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+8tugUMzatttu8qAgjH/Y6" Cancel-Lock: sha1:nOAF0ENPPAkouSxuY/by9QBdTxw= X-newsreader: xrn 10.11 Bytes: 2376 Stefan Monnier writes: >> A C64 had 64K 8-bit bytes of RAM, > >Indeed (tho, IIRC 8kB of those were hidden by the ROM, tho you could >change the mapping to hide different 8kB at different time and thus >access the full 64kB of RAM). Actually, the C64 has 8+8KB of ROM (at $a000-$bfff and at $e000-$ffff), and I/O at $D000-$DFFF and at $0-$1 that hide the RAM in the default configuration. You could configure the "MMU" to make all RAM except the two locations at $0-$1 readable and writeable for the CPU, but of course then you would have to bank-switch to access the I/O or the OS (in the ROM at $e000-$ffff), so the common setup even if BASIC was not needed was to have the I/O and the OS ROM visible, and 48KB of contiguous RAM readable and writable. >> and the floppies held about 1.2MB but they were a >> whole lot cheaper than 1311 disk packs. > >IIRC they held only ~170kB. Yes, the 1541 gave us 170KB at a time. Much later there was also the 1571, which was double-sided and thus doubled the capacity, and even later the 1581 which gave 790KB of storage. I stuck with the 1541, for which I have an accelerator add-on. - anton -- 'Anyone trying for "industrial quality" ISA should avoid undefined behavior.' Mitch Alsup,