Ref: 05290003
Title: 3Com 320 MB Hard Disk Drive Release Note
Date:  4-24-89

Copyright 3Com Corporation, 1991.  All rights reserved.

3Com 320MB Hard Disk Drive Release Note - Number 6333-00

Note: If you are using 3+Open, or a version of 3+ later than 1.3.1,
the 320MB drive may be documented in your server guide.  If this is
the case, use the procedures in your server guide instead of this
release note, and discard the diskettes shipped with the drive:  they are
not required.

This note documents the 320MB hard disk drive.  The 320MB drive is
available in two forms:

.br;As a hard disk drive option
.br;Installed as the first drive in a 3Server Expansion Unit

The 320MB hard disk drive option may be installed as the second
drive in either a 3S/400 or a 3Server Expansion Unit.  The first
drive in the expansion unit may be either 150MB or 320MB.

The 320MB Expansion Unit may be used with a 3S/400 or a 3S/401.
If a second drive is installed in the expansion unit, it may be either
150MB or 320MB.

.br;A 150MB drive is documented in these manuals:
.br;3Server386 Guide
.br;3Server Expansion Unit Guide

Use the disk drive option installation procedures in these manuals for
the 320MB hard disk drive.  The 320MB hard disk drive uses the same
Adaptec ACB-4525 controller as the 150MB drive, configured exactly the
same way.  The 320MB drive installs in exactly the same way as the
150MB drive, and has the same general appearance.

Note:  The controller for both the 150MB and 320MB disk drives is the
Adaptec 4525.  With the introduction of the 320MB drive, the PROM on
the controller has been upgraded.  The upgraded PROM, labelled 4525C,
is compatible with both the 150MB and 320MB drives.  You cannot use a
controller from a 150MB drive, with a 4525B PROM, on a 320MB drive.  All
320MB drives are shipped with the correct PROMs installed, and under
normal circumstances, you should never have to separate the controller
and drive.

There are new system software diskettes shipped with the 320MB drive.
Use these new diskettes instead of your old ones.

There is a new version of 3DISK386 on System Software #1 which has
entries for all of the controllers and drives supported by 3Com.
When using this new version, remember that your controller is an
Adaptec ACB-4525 with a 320MB drive.  When using the new 3DISK386,
you will see more menu options than those documented in your current
3Server386 Guide, but the program generally operates the same way.
The new choices include:

.br;150MB or 320MB drive:
.br;Drive type?
.br;1. 150 MB ( 969 Cyls,  9 Heads, 36 Sectors/track)
.br;2. 320 MB (1224 Cyls, 15 Heads, 36 Sectors/track)
.br;3. Others :

.br;3+Open or 3+ network software:
.br;Choose target system
.br;1. 3+Open
.br;2. 3+
.br;A new main menu option (Format a single partition) that
allows you to purge the contents of a partition.

To make room for the new 3DISK386 program, the SETUP program
has been deleted from System Software #1.  SETUP is on System Software #2.

The 320MB drive is factory formatted to have 512 bytes per sector
and 4 sectors per cluster.  There are ten 31MB volumes and one 11MB volume.
The drive is not formatted as bootable.

Table 1 lists the various disk formats that can be used with 3+
network software.  The limit of 16,374 clusters per volume is
imposed by the DOS CHKDSK command.  If this limit is exceeded,
CHKDSK cannot be used to repair the volume should corruption occur.

Table 1.  3+ Network Software Disk Formats
SectorsClustersSectorsBytesBytesBytesMB
perperperperperperper
ClusterVolumeVolumeSectorClusterVolumeVolume
116,37416,3745125128,383,4888
1,0241,02416,766,97616
2,0482,04833,533,95232
4,0964,09667,067,90464
8,1928,192134,135,808128
16,38416,384268,271,616256

216,37432,7485121,02416,766,97616
1,0242,04833,533,95232
2,0484,09667,067,90464
4,0968,192134,135,808128
8,19216,384268,271,616256
16,384

With 2 sectors per cluster, sectors larger than 8,192 bytes would
exceed the maximum cluster size of 16,384.

416,37465,4965122,04833,533,95232
1,0244,09667,067,90464
2,0488,192134,135,808128
4,09616,384268,271,616256
8,19216,384

With 4 sectors per cluster, sectors larger than 4,096 bytes would
exceed the maximum cluster size of 16,384.

Note:  The configurations above are limited by the maximum number of
clusters per volume (16,374).  Table continues on the next page.

Table 1.  3+ Network Software Disk Formats (Continued)
SectorsClustersSectorsBytesBytesBytesMB
perperperperperperper
ClusterVolumeVolumeSectorClusterVolumeVolume

88,19265,5365124,09633,554,43232
1,0248,19267,108,86464
2,04816,384134,217,728128
4,0968,19216,384

With 8 sectors per cluster, sectors larger than 2,048 bytes would
exceed the maximum cluster size of 16,384.

164,09665,5365128,19233,554,43232
1,02416,38467,108,86464
2,0484,0968,19216,384

With 16 sectors per cluster, sectors larger than 1,024 bytes would
exceed the maximum cluster size of 16,384.

322,04865,53651216,38433,554,43232
1,0242,0484,0968,19216,384

With 32 sectors per cluster, sectors larger than 512 bytes would exceed
the maximum cluster size of 16,384.

Note:  The configurations above are limited by the maximum number of
sectors per volume (65,536).

Release Note: 6333-00
