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Path: sserve!manuel.anu.edu.au!munnari.oz.au!spool.mu.edu!uwm.edu!zaphod.mps.ohio-state.edu!cs.utexas.edu!rutgers!jvnc.net!nuscc!ntuix!eoahmad From: eoahmad@ntuix.ntu.ac.sg (Othman Ahmad) Newsgroups: comp.unix.bsd Subject: Re: DOS and 386BSD (and NT and OS2) Message-ID: <1992Oct21.160231.6516@ntuix.ntu.ac.sg> Date: 21 Oct 92 16:02:31 GMT References: <1992Oct16.175743.19250@fcom.cc.utah.edu> Organization: Nanyang Technological University - Singapore Lines: 88 X-Newsreader: TIN [version 1.1 PL6] A Wizard of Earth C (terry@cs.weber.edu) wrote: : I can definitively say that the IDE on AT&T 386SX WGS and Compaq Deskpro : 486/33M boxes use *soft* translation... that is, the translation is done This can't be. It will mean that 386BSD can never access your IDE hard-disk. Also this IDE hard-disk cannot be used by any other PCs except the original manufacturer. If you can transfer this IDE hard-disk, to another PC, and works , then IDE translation is in hardware. REmember that IDE controller has no nothing, only wires extending the isa connector to the IDE hard-disk. How can it contain any bios rom uniqe to it?? SO THE softw translation must be on the system BIOS itself. This is a very stupid design decision and defeats the portability of IDE. : in software as a result of using the BIOS. I can also say that the : Maxtor ESDI drive on my WD1007 uses hardware translation, independant of : the use of the BIOS. THE IDE hard-disk can have this ESDI controller which is shrunk to fit on the hard-disk itself. IDE controller does not have a "controller". : : >>There is a probe request (which not all controllers support!) that is done : >>to ask the controller the disk's geometry. This is because the raw driver : >>used in 386BSD doesn't use the BIOS (for reasons which should be obvious) : >>and talks to the controller directly -- thus there is no such thing as a : >>translated geometry as far as 386BSD (or any other non-BIOS OS) is : >>concerned. : > : >As I said above, the first access that the kernel does actually be in : >translated mode. If you put translated parameters into your disklabel : >it should continue to run in translation mode for all your work and : >no-one would be the wiser (may be a bit slower). I think that in a : >translating controller, the translation is done whether or not it's the : >BIOS that is making the requests. Non translation is often only a case : >of 1:1 translation. : : This is true for ESDI and SCSI, but not for the IDE I have played with : so far. The biggest problem here, of course, is that IDE "controllers" : are pretty much stuck on the disk drive, and the "controller card" you : put in the DOS box is more of a bus interface than anything else. This : is why IDE controllers are so cheap compared to SCSI. In plain English This is reason IDE is faster and more reliable than anything else. The signal path does not exist, unlikde ESDI , and there is only one controller, unlike 2 for SCSI, less communication overhead. SCSI 2 looks fast because it has 32-bit bus between controllers, but it still has to communicate via ISA 16-bit bus, even if you have the 32-bit EISA bus, the speed of the EISA bus may not match with the speed of the SCSI-2. ISA bus is still much faster than any hard-disk controller. : (yuck! 8-)), this means it's possible for this to vary between hardware : and software for different IDE drives. The wonderful thing here is that : using two different drives with soft translation turned off basically : requires two CMOS entries where only one is possible. CMOS entries are used by DOS only. Not by 386BSD. I can run 386bsd only hard-disk even if it does not match the CMOS entry. 386bsd actually initialised the IDE hard-disk to the entry in disklabel, not from CMOS entry. I'm not sure how dist.fs gets the disk geomety. CMOS or on hard-disk. Most probably from CMOS. : : >well I don't think this is correct.. as I said before, the very first seek : >the kernel does is in translated mode and it has to read the bootblock to : >work out what the translated geometry is, so it can find the disklabel. disklabel is in bootblock. If the bootblock is corrupted, then it cannot find the correct 386bsd partition. : : This isn't a really valid test. I would ammend it to "get a translated : IDE to work for 386BSD with DOS partitioning active on the disk"... even : then, I'd hate to buy off on it, as I have suggested two ways of doing : this, and you have suggested a third (below) with the translation on : for DOS but off for 386BSD. IDE will not work without any translation. It is just a matter of using different default geometries. : "I have an 8 user poetic license" - me : Get the 386bsd FAQ from agate.berkeley.edu:/pub/386BSD/386bsd-0.1/unofficial : ------------------------------------------------------------------------------- -- Othman bin Ahmad, School of EEE, Nanyang Technological University, Singapore 2263. Internet Email: eoahmad@ntuix.ntu.ac.sg Bitnet Email: eoahmad@ntuvax.bitnet