Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!mcvax!unido!fauern!immd4.informatik.uni-erlangen.de!mlelstv From: mlelstv@immd4.informatik.uni-erlangen.de (Michael van Elst ) Newsgroups: comp.sys.amiga Subject: Re: Are there any programs that allow reading Apple ][ disks? Keywords: disk encoding, MFM, GCR, 13-sector, 16-sector, ProDOS, 5.25, 3.5 Message-ID: <491@medusa.informatik.uni-erlangen.de> Date: 18 Aug 89 14:12:53 GMT References: <495@tardis.Tymnet.COM> <15704@pollux.UUCP> <12938@grebyn.com> Organization: IMMD IV, University of Erlangen, W-Germany Lines: 23 ckp@grebyn.com (Checkpoint Technologies) writes: >In article <15704@pollux.UUCP> bjc@pollux.UUCP () writes: >> >>The RKM states that the GCR capability in the Amiga is the Apple version. >> >As far as I know, the Amiga does not have a GCR translation table built >in. It does have the ability to read CGR disks (witness: Disk-2-Disk and >Mac-2-Dos and AMAX), but this is because the Amiga's disk controller >gives the CPU data below the formatter level, so the CPU can perform >whatever encoding it desired. There is a limited hardware feature for GCR decoding. It allows less CPU overhead when reading Apple-II style GCR code.. The Apple-II uses a simple shift register that samples raw data (just like the Amiga hardware) and transfers it's contents into a latch everytime the MSB (bit 7) is equal 1, then the shifter is cleared. A similar mode can be used with the Amiga hardware. Michael van Elst E-mail: UUCP: ...uunet!unido!fauern!immd4!mlelstv