jearly@lehi3b15.csee.Lehigh.EDU (John Early) (08/20/90)
A few days ago I posted a list of some hard drive prices (mostly 335 meg ESDI drives ranging from $800-$1100) but didn't include the name of the company selling them. Since then many people have writen asking for the name, and I have sent it to them. However, over 20 messages have bounced back to me, and I'm going away for a weeks vacation, so here is the name of the company: Corporate Systems Center 730 North Pastoria Ave. Sunnyvale, CA 94086 (408) 737-7312 fax (408) 737-1017 Sorry for any confusion. John. ---------------------------------------- John Early | jearly@lehi3b15.csee.lehigh.edu | I was just a child then; JPE1@Lehigh.Bitnet | now I'm only a man. [pf] LUJPE@VAX1.cc.lehigh.edu |
jdwhite@iastate.edu (White Jason David) (12/13/90)
Is is possible to have two different hard drive controllers on one machine. I.E. a RLL controller and an IDE controller, each with a hard drive? -- J. White |} jdwhite@iastate.edu "Ah, I see you have the machine that goes PING!" | hzl09@isuvax.BITNET
davidsen@sixhub.UUCP (Wm E. Davidsen Jr) (12/13/90)
In article <1990Dec13.012237.22378@news.iastate.edu> jdwhite@iastate.edu (White Jason David) writes: | Is is possible to have two different hard drive controllers on one machine. | I.E. a RLL controller and an IDE controller, each with a hard drive? You can have a mix of MFM, RLL, and ESDI with UNIX. With DOS you can mix if the BIOS can be readdressed and the controller supports being put at a secondary address. I don't know what magic you need to make the o/s use the 2nd controller in DOS, in theory it should create the device control blocks during init. -- bill davidsen - davidsen@sixhub.uucp (uunet!crdgw1!sixhub!davidsen) sysop *IX BBS and Public Access UNIX moderator of comp.binaries.ibm.pc and 80386 mailing list "Stupidity, like virtue, is its own reward" -me
kaplin@acsu.buffalo.edu (leo kaplin) (06/27/91)
Can somebody tell me what does the RLL and MFM stand for when talking
about hard drives.
thanx, Leo
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Leo Kaplin, State University of New York at Buffalo, Dept. of Computer Science
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Leo Kaplin, State University of New York at Buffalo, Dept. of Computer Science
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UUCP: ...!{rutgers,uunet}!cs.buffalo.edu!kaplin gerardka@hobbes.ism.isc.com (Gerard Kam) (06/27/91)
In article <81360@eerie.acsu.Buffalo.EDU> kaplin@acsu.buffalo.edu (leo kaplin) writes: >Can somebody tell me what does the RLL and MFM stand for when talking >about hard drives. > >thanx, Leo MFM: Modified Frequency Modulation a method of storing digital data as a bit stream on an analog medium (in disk drives, this is usually a ferric oxide). RLL: Run Length Limited a digital encoding which increases the length of the data, but allows much higher effective bit density. Typically used with MFM recording. The higher bit density is achieved because the recording density is set to cope with worst case flux reversals. By encoding the data to new bit patterns that do not generate as many flux reversals, the new "worst case" is predictable, and allows a higher flux density. The encode on write and decode on read is done by the disk controller. The drive must be capable of the slightly higher transfer rates. Disks with embedded controllers such as SCSI and IDE usually are MFM with RLL. But since they have a digital interface, the Host computer does not have to be concerned with such details. "Bare" drives such as ST506/412 or ESDI require a controller of a matching type so that the serial data to/from the drive is interpreted properly to data bytes (records). Gerard