Release August 18, 1986 Number 147


PREPARE Utility on the Initial SFT I Version 2.0a Release


A problem has been encountered in the PREPARE utility of the initial release
of SFT I version 2.0a.  The PREPARE utility reads a list of bad blocks found
in the bad block table (sectors 18 and 19) and redirects them to good
blocks.  Associated with each redirected block is a status byte which is
used by SFT I to determine if the sector contains valid data.  The problem
was created by PREPARE erroneously copying the status byte of the bad block
over the status byte of an otherwise good block in the redirection area.
This caused the network to think that a block contained invalid data when in
fact the data was valid.  The status byte of the redirected blocks would
only clear itself when a write operation reset the status byte on the
redirected blocks.

The problem of the erroneous status byte became apparent when the INSTALL
utility was executed after the PREPARE utility had already redirected the
bad blocks.  The INSTALL utility does a "pre-read" on the area where the
system is to be installed.  If the INSTALL utility finds that the status
byte of the redirected blocks is flagged as containing bad data, the error
message "Error writing file" is displayed.  This problem usually does not
occur on disk drives with few or no bad blocks.

To fix this problem, a new version of PREPARE (Rev. B) has been created.  As
of Aug 18, 1986, the current release of the INSTALL diskette for SFT I has
been upgraded to include the new PREPARE utility.  All subsequent shipments
of SFT I will include the new INSTALL diskette.

Any customer who received SFT I prior to Aug 18, 1986 will receive a new
INSTALL diskette containing the new PREPARE utility.  The list on page two
comprises all the serial numbers of the SFT I systems that were sent out
prior to this date.  If the serial number of your system is listed, a new
INSTALL diskette will be set to you automatically.

S/N OF SFT I TO BE UPDATED
28578             28581            28584            28586
28595             28599            28623            28632
28645             29614            29634            28227
28232             28244            28245            28256
28555             28557            28559            28561
28566             28569            29662            29717
29721             29722            29723            29746
29972             29977            502043           502068
502070            502071           502072           502079
502080            502082           502083           502084
502087            502095           502098           502101