Path: utzoo!attcan!uunet!cbmvax!jesup
From: jesup@cbmvax.UUCP (Randell Jesup)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 2090A speed
Message-ID: <5507@cbmvax.UUCP>
Date: 15 Dec 88 00:28:55 GMT
References: <14015@cisunx.UUCP> <1135@esunix.UUCP> <9472@gryphon.COM> <183@sns.UUCP>
Reply-To: jesup@cbmvax.UUCP (Randell Jesup)
Organization: Commodore Technology, West Chester, PA
Lines: 22

In article <183@sns.UUCP> space@sns.UUCP (Lars Soltau) writes:
>Could you explain the difference between hard and soft format? I mean, how do
>I hard format an SCSI device? Via prep, which does take much longer with an
>SCSI HD than with an ST506 HD?

	"Hard" format (also known as "low-level" format) is what decides which
sectors will be in what positions on a track (interleave).  On a SCSI drive,
hard format also maps out any bad sectors on the drive, so you'll never see
them.  This requires testing the entire disk, which can take a while.  ST-506
disks don't do this, so a low-level format in prep only actually modifies
the first 2 cylinders, where prep stores it's bad block info and first
partition info.

	"Soft" format (or high-level format, or AmigaDos format) is what
sets up a disk structure on a partition of a drive.  It may also (if you don't
use the "quick" option) test every sector of the partition by reading and 
writing it.  You cannot change the interleave with a soft format, since 
interleave applies to the whole disk.

-- 
You've heard of CATS? Well, I'm a member of DOGS: Developers Of Great Software.
Randell Jesup, Commodore Engineering {uunet|rutgers|allegra}!cbmvax!jesup