Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ames!amdcad!sun!pitstop!sundc!seismo!uunet!steinmetz!davidsen From: davidsen@steinmetz.ge.com (William E. Davidsen Jr) Newsgroups: comp.sys.ibm.pc Subject: Re: Hard Disks: XT vs. AT Keywords: hard disk xt at Message-ID: <11517@steinmetz.ge.com> Date: 13 Jul 88 14:50:47 GMT References: <6201@megaron.arizona.edu> Reply-To: davidsen@crdos1.UUCP (bill davidsen) Organization: General Electric CRD, Schenectady, NY Lines: 34 In article <6201@megaron.arizona.edu> cjeffery@arizona.edu (Clinton Jeffery) writes: | Hi people: for a year now I have been running an Atasi 3046 drive in my | XT clone. Recently I purchased an AT clone kit, planning on using the | Atasi as its hard drive. So far, the hard disk "fails initialization" | and has resisted any attempts at low-level formatting in the AT. I believe that AT disks are *not* ST506, they are ST412. The difference in the two standards is that seek commands are buffered for ST412 and the wait comes at the end. BIOS commands to step five tracks: ST506 ST412 step step wait step step step wait step step step wait wait step wait step wait Looking at the standards as presented in a short article I found, this apperas to be the only difference, but it's enough to make the ROM BIOS on the disk controller not work. Warning: this is my understanding of the matter, but I don't sell or service disk drives. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me