All things ESDI

On 5/4/05, Parker, Kevin <KParker at workcover.com> wrote: Ick. I tried resurrecting some old ESDI drives a few years ago while rebuilding my PS/2 Model 80-A21. I managed to obtain MCA, ISA & EISA controllers and a bag of cables for free to go with the 2 or 3 drives I had. I used to install & run loads of these things in the late 1980s. I couldn't get a single one going. Endless errors about drives not found or not responding. In the end I gave them all to a mate of mine rebuilding a PDP/11 who has vastly more low-level knowledge than I - he writes BIOSes for a living. Same cables as MFM or RLL, yes, and software-compatible. AIUI it was essentially higher-performance RLL which moved more of the controller logic from the host adaptor onto the drive itself for better speed, a trend that ultimately resulted in IDE a few years later. IDE is also called ATA, of course, for AT-attachment - these drives are smart enough to connect straight into an AT (ISA) bus. ESDI was common in high-performance machines and for "large" drives - 120MB was about the smallest I saw (when 20MB - 40MB was still common) and ~330MB was typical. I have heard of ~600MB units but never installed one. It's an Int11 device, just like an ST-506 drive. The BIOS needs to be configured with the right number of heads, cylinders and sectors-per-track, tho' picking type 20 or so will usually give you enough to boot and read the true settings off the drive itself. They will probably need to be low-level formatted if moving them from one controller to another. DEBUG and then G=c800:5 is what I dimly recall for this, tho' in later years I used CheckIt or even SpinRite to do this. -- Liam Proven Home: http://welcome.to/liamsweb * Blog: http://lproven.livejournal.com AOL, Yahoo UK: liamproven * ICQ: 73187508 * MSN: lproven at hotmail.com