On Mon, 12 Jun 2000, Greg Woods wrote: > > Alexander Clouter wrote: > > > due to microsofts infinite wisdom dos (and so windoze) has trouble > > handling more than 1024 cylinders (if I remember correctly). > > Much as I love a good M$-bashing occasionally, I don't think this is > Microsoft's doing. The 1024 cylinder limit was in the original design of > the PC BIOS. Those engineers just couldn't see that anyone would ever > have a 30GB disk drive on a PC :-) > > On most PC's, running any kind of modern operating system (including > Windoze), the 1024 limit only applies at boot time. Whatever program is > loaded at boot time must not be stored beyond cylinder 1024. I am told > that there are some newer BIOS's that can play games with the disk > geometry and translate block and cylinder numbers on the fly, to make it > look like the disk has a different geometry than it actually has, and > get around this limitation. But that is a function of the BIOS, not the > operating system. > actually from what I've read the old BIOS indeed couldn't use do more than 1024 cylinders however that was easily changed. The problem lay in how MS-DOS calculated the amount of disk space available for using CHS. However due to a useful feature more than 1024 cylinders could not be identified. To overcome this problem LBA (or something like it) was used to translate a 'virtual' CHS to real CHS. This is usually done by the BIOS however sometimes a software patch instead had to be used (causing a slight performance hit).
Alex -- ** ((__)) Alexander "Jim diGriz" "Hubenko" Clouter \\ ((oo)) \\------\\// e-mail: [EMAIL PROTECTED] || || |||----||| ~~~ ~~~ equip : 300Mhz Celeron Laptop running Cow during an Debian Woody Linux Earthquake
