Path: utzoo!attcan!uunet!seismo!dimacs.rutgers.edu!rutgers!apple!agate!darkstar!ucscb.UCSC.EDU!tmaster From: tmaster@ucscb.UCSC.EDU (The Master) Newsgroups: comp.sys.apple2 Subject: Re: Apple /// Message-ID: <8555@darkstar.ucsc.edu> Date: 6 Nov 90 00:05:04 GMT References: <9011051918.AA26746@apple.com> Sender: usenet@darkstar.ucsc.edu Organization: University of California, Santa Cruz; Open Access Computing Lines: 67 In article <9011051918.AA26746@apple.com> Joe_Luzzi.FULLERTON_CC@QMBRIDGE.CALSTATE.EDU (Joe Luzzi) writes: > > Time: 10:00 AM > Date: 10/26/90 >Subject: Apple /// >With all this talk about Apple ///, I'm curious as to the specifics of the >machine: cpu, memory size, etc... What made it different than the II? > >Thanks. Apple /// was a more powerful machine than than ][, and arguably even more powerful than a //e or //c. What it had: 6502 microprocessor running at 2 mhz peak. The processor slows down for memory refresh and screen refresh, giving effective speed of 1.4 mhz. However, screen refresh can be turned off, so it operates at 1.8 mhz (not that for certain devices it also slows down for 1 mhz.) 128k ram minimum. There were two piggyback memory boards produced by apple - one and only one was always installed. The 12 volt version would support up to 128k, the 5 volt would go up to 256k. On Three produced one which would go up to 512k which is the maximum memory that the apple /// can handle as 'normal' memory. The memory was managed by bank switching (address 0-2000 and A000-FFFF would always be in memory, and you bank switch in the 2000-BFFF range.) Also enhanced indirect addressing allowed loading/storing of values in other banks. The mechanism behind this was you use and indirect store on the zero page, and in another location (+1600 from zero page) you stored the bank number. The system had 80 columns built in along with upper and lower case. The entire system was ram based, including the character set (128 distinct printing characters + the inverse of these characters) and keyboard layout. It also supported a 40 column color text mode where the foreground and background color of each character position could be specified (16 colors available.) Its graphics modes were 140x192, 280x192 (two of these with varying color restrictions) and 560x192. It has a built is rs232 port, video port (which with simple circuit can be used to drive a rgb monitor), 2 game ports (one of which can be used for a silentype printer) and a disk drive port in which up to 3 disk ///'s (140k drives) could be hooked up (The system has 1 interal drive.) It also has 4 slots, with very similiar pinouts to the normal apple // slots. It was designed to have a clock built in, but the company that was supposed to make the clock chip didn't finish it on time. However, the chip is now available for about $10, so plug that in plus a few batteries for backup and you have a clock also. Ulike the //e however, which used many custom chips to keep the chip count low, the apple /// uses pretty all standard ls chips plus a few roms and proms. The chip count, not including ram, is around 100. SOS, the Sophisticated Operating System, stores files in the same way as prodos. To make a sos call, a break instruction is used with the call code and a pointer following the break. It supported interrupts, so devices such as the serial port and keyboard has buffering. The Master tmaster@ucscb.ucsc.edu