dlyons@Apple.COM (David Lyons) (08/26/89)
In article <4852@portia.Stanford.EDU> kodali@Portia.Stanford.EDU (Chan Wilson) writes: >[...] But I've always wanted to know how >Apple manages to have a selectable $C000 space... Are you asking about the $C800..$CFFE space? I thought that was described pretty well in the reference manuals, but maybe not--I haven't looked it up lately (when I did, it was in my II+ manual). All Apple II models have this: each card can use the $C800 space (2K) for whatever it wants (RAM, ROM, I/O locations, or whatever), but only one card "owns" it at a time. When $CFFF is read or written, all cards turn *off* their ownership of that space; when $Cnxx is read or written, slot N owns that space. (The card that owns it needs to store its slot number in $07F8, so that the system can restore the ownership properly after handling an interrupt.) The enhanced IIe and some models of the IIc have additional ROM that can be switched in in the $C100..$CFFF space--this is handled with $C0xx softswitches known to the main ROM of each machine. (Did that answer the question?) >Also, if I put an Appletalk card in my ][+, can I use it? No, I don't think so--the ROM on the card needs a 65C02 and may also require ROM routines that aren't present in the II+. All the software Apple provides for AppleTalk requires IIe-style 128K and IIe-style 80-columns. >--Chan >kodali@portia.stanford.edu --Dave Lyons, Apple Computer, Inc. | DAL Systems AppleLink--Apple Edition: DAVE.LYONS | P.O. Box 875 AppleLink--Personal Edition: Dave Lyons | Cupertino, CA 95015-0875 GEnie: D.LYONS2 or DAVE.LYONS CompuServe: 72177,3233 Internet/BITNET: dlyons@apple.com UUCP: ...!ames!apple!dlyons My opinions are my own, not Apple's.
kodali@portia.Stanford.EDU (VAS KODALI) (08/28/89)
In article <34349@apple.Apple.COM> dlyons@Apple.COM (David Lyons) writes: >In article <4852@portia.Stanford.EDU> kodali@Portia.Stanford.EDU (Chan Wilson) writes: >>[...] But I've always wanted to know how >>Apple manages to have a selectable $C000 space... > >The enhanced IIe and some models of the IIc have additional ROM that can >be switched in in the $C100..$CFFF space--this is handled with $C0xx >softswitches known to the main ROM of each machine. > >(Did that answer the question?) Uhmm.. yes, it did. In another vein, will there be a 'segmentg' option added to Shrinkit, similar to Stuffit for the Mac? I shrinked the contents of my hard disk, resulting in a large file that won't fit on a floppy... oops. --Chan kodali@portia.stanford.edu