Newsgroups: comp.sys.apple2 Path: news1.icaen!news.uiowa.edu!chi-news.cic.net!su-news-hub1.bbnplanet.com!cpk-news-hub1.bbnplanet.com!cam-news-hub1.bbnplanet.com!news.bbnplanet.com!howland.erols.net!usc!newshub.cts.com!crash!pro-nsdapple!tomk From: tomk@pro-nsdapple.cts.com (Tom Kelly) Subject: Re: External 3.5 Drive and //c HELP Organization: ProLine [pro-nsdapple] - North San Diego Apple Users Group Date: Mon, 24 Mar 97 22:57:00 PST Message-ID: References: Lines: 67 In nobody@aol.com (nobody) writes: > > I just picked up an external 3.5 drive for Apples. It plugs in to the back >of my //c and such. When I go to init blah,d2 the light comes on but it >doesn't spin up. Also the disk won't eject. I assume that it's a cable issue. > Does anyone have any information on how to hook this to the //c??? > > >Thanks! > The ROM change and changes noted below will enable the earliest IIc to use a UniDisk 3.5. This will NOT fix the problem that model may have with faster modems. To find out which //c ROM version you have, go into BASIC (or if you don't have a disk handy, just turn on the computer and hit ctrl-reset after you see the "Check disk drive." message) and type the following line and hit return at the "]" prompt: PRINT PEEK (64447) If you get the number "255", then you have the original //c ROM. To be able to use the UniDisk 3.5, you will have to upgrade to a newer version of the ROM. Values of the PEEK (64447) are as follows: 255 Original //c ROM (Can't use UniDisk 3.5") 0 3.5 ROM //c (CAN use UniDisk 3.5") 3 Original "Memory-expandable" //c (CAN use UniDisk 3.5") 4 Revised "Memory-expandable" //c (CAN use UniDisk 3.5") 5 Apple //c+ (built-in 3.5" drive; can use Unidisk 3.5" AND Apple 3.5") For those of you who might be interested in other differences between //c ROM versions, see Apple // Tech Note #7 for the Apple //c. The original ROM is 16K (27128 or equivalent) P/N (342-0272-A) Print Peek(64447) = 255 The newer ROM (UniDisk 3.5) is 32K (27256 or equivalent) P/N (342-0445) Print Peek(64447) = 0 =========================================================================== This info came from many sources. David Empson was a major source for me. David Empson dempson@actrix.gen.nz Snail Mail: P.O. Box 27-103, Wellington, New Zealand =========================================================================== You must have the proper 3.5" drive (UniDisk) and a IIc with the ROM that supports the drive. Otherwise you can NOT use a 3.5" drive. PS I have a ROM for sale, if you need it,send me E-Mail. ---- ProLine: tomk@pro-nsdapple Internet: tomk@pro-nsdapple.cts.com UUCP: crash!pro-nsdapple!tomk