Path: utzoo!utgpu!attcan!uunet!ingr!b11!jim
From: jim@b11.INGR.COM. (Jim Levie )
Newsgroups: comp.sys.amiga.tech
Subject: Re: 2090A speed
Summary: Bad block handling
Message-ID: <328@b11.INGR.COM.>
Date: 15 Dec 88 19:22:11 GMT
References: <14015@cisunx.UUCP> <1135@esunix.UUCP> <9472@gryphon.COM> <183@sns.UUCP> <5507@cbmvax.UUCP>
Reply-To: jim@b11.UUCP (Jim Levie )
Organization: Far from the halls of Amber
Lines: 42

In article <5507@cbmvax.UUCP> jesup@cbmvax.UUCP (Randell Jesup) writes:
>
>	"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.
>

Well lets see now Randell has essentially said:

1) SCSI maps out bad blocks when the low-level formatting is done and 'prep'
   does this.

2) 'prep' only sets up the first 2 cylinders "where bad block info ..."
   is stored for ST506 drives and prep wants the user to enter the bad
   blocks in terms of head, track, and BFI.

3) The DOS format can do a read and write of every sector.

The question is does format add to the badblock information for SCSI or ST506
drives?  It would seem to me that one of the things either format or some
other utility should do is to find and report badblocks that are present on
hard disks and also update the bad block data on the drive. When the bad blocks
are reported they should be in a form suitable for input to "prep' to avoid
having to scan for them in the future.



-- 
=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
 Jim Levie   REMTECH Inc  Huntsville, Al 
 The opinions expressed above are just that.
 Ph.    (205) 536-8581               email: uunet!ingr!b11!jim