Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!cayman!carl From: carl@caicos.cayman (Carl Heinzl) Newsgroups: comp.sys.ibm.pc.hardware Subject: Re: Two IDE questions Message-ID: Date: 17 May 91 14:04:41 GMT References: <1991May14.052800.26878@ux1.cso.uiuc.edu> Sender: news@cayman.COM Organization: /home/carl/.organization Lines: 28 Nntp-Posting-Host: caicos In-reply-to: phil@ux1.cso.uiuc.edu's message of 14 May 91 05:28:00 GMT >>IDE Drives are VERY different. Statements like "IDE offers better performance >>than MFM and ESDI" are false simply because some IDE drives use MFM encoding, >>some use RLL, etc. >How does one tell the difference? Don't know, sorry... >And how many different encoding systems, or other things, are relevant? >Is ESDI its own encoding system? No, ESDI is a difference in the interface. Every ESDI disk that I have ever used uses an RLL (2,7 RLL was the exact definition, I believe) encoding method. I don't know if any MFM disks operate at >5 Megabits/second, but ESDI disks go as high as 24 Mb/s with 10 and 15 mb/s pretty common (on the Maxtor's for example). 15 mb/s (and the lower latency, around 16-18 ms for Maxtor) is pretty nice after you've dealt with some old 28 ms MFM disks for a while. -Carl- -- ******************************************************************************* Carl G. Heinzl - WA3UEN Internet: carl@cayman.com Cayman Systems, Inc Phone: 617/494-1999 x208 26 Landsdowne Street FAX: 617/494-9270 Cambridge, MA 02139 AppleLink: D0523