[comp.sys.nsc.32k] 9380S disk format question

eyal@echo.canberra.edu.au (Eyal Lebedinsky) (11/14/90)

Hello,

I was wondering how the disk is organized. Doing some number juggling I
concluded that the disk is organized as:
1219 cylinders (+5 spare)
15 heads * 36 sectors = 540 - 4 spare = 536 sectors used
disk capacity = 1219*536 = 653384 blocks = 319Meg.

Now, from other sources I find that the disk can be had in a 1Kbyte sector
configuration, 19 sectors/track. This will add up to about 335Megs available.
That is 16Megs extra, blocksize = minix blocksize.

The question: can the SCSI device be reformatted? easily? I mean with just some
software, no special manufacturer utilities.

-- 
Regards
	Eyal

dave@quick.com (David A. Wilson) (11/15/90)

This is how I do it for a cdc4702n(702MB unformatted) disk, I think it
should work in general.

1. Formatting from scratch

	a: set block size:

		SCSI cmd bytes(hex)
			15	Command=Mode Select
			11	PF=1, SMP(save parameters)=1
			00
			00
			0C	Parameter list length
			00
		SCSI data bytes to write(hex)
			00	Mode select hdr
			00	Medium type
			00
			08	Block descriptor length
			00	Density code
			00	|
			00	|- # of blocks(0=all)
			00	|
			00
			00	|
			xx	|- block size for format
			00	|
		
		Where xx is: 10=4096, 08=2048, 04=1024, 02=512, 01=256.

	b. Format Drive

		SCSI cmd bytes(hex)
			04	Command=Format unit
			00	Defect list mode
			00
			00	|- Interleave(default[0] means 1:1)
			00	|
			00
		# of SCSI data bytes to read(decimal)
			8
		
		I don't think read bytes are needed, but it didn't hurt.


====== I hope this is useful

	David A. Wilson
	dave@sea375.uucp
	...uw-beaver!uw-entropy!quick!sigma!sea375!dave