Ref: 08740008
Title: Special Notes on Memory requirements for 3S40X
Date:  07/15/88

Copyright 3Com Corporation, 1991.  All rights reserved.

As many of you have discovered not as many services fit on a 3S/400
server as fit on a 3S/200 server.  This change reflects some
growth in code size (approximately 70 KB) and higher parameter
settings (approximately 55 KB) over 3S/200 code and parameter
settings.

Features and performance vs memory requirements is always a
difficult trade-off to balance.   In the 3S/400 we believed that
the trade-offs made would provide valuable functionality to our
customers.  While we incorporated these trade-offs, however, we
did not communicate all aspects of their consequences.

To clarify the
memory requirements of the 3S/400, the following section outlines
the memory per service required on the 3S/400 as compared to the
3S/200.  This will allow you to easily understand and calculate
the types and number of services that can be loaded on a 3S/400.

BUT also remember

- That the 3S/400 has features and benefits not available on the
3S/200.   Often these are more important than getting ALL services
on one server and can become the decision point in selecting a 400
over a 200 server.

3S/400 features, such as:

.br;* 2 to 2.5 times the performance
.br;* Powerfail support
.br;* 3+Open (OS/2) ready
.br;* Support for additional printer and communication ports
.br;* NetConnect for Token-to-Token bridging
.br;* New easy Quick installation (<15 minutes)
.br;* Better price/performance
.br;* 5MB/min. backup (vs. 1MB/min. on 3S/200)
.br;* Send/Receive broadcast utility

provide important functionality not available on 3S/200s.

- Only ONE Start, Backup, Name and locator service are needed
per network.  Only customers running Netbios applications
need locator.

- Services such as Locator and Route/Remote/NetConnect can run
on 3Stations and concurrent servers (in DOS mode), thereby
allowing all other 3+ services including 3+Backup to be run
on a network with a 3S/400 server.   For performance it is
best to distribute File and Communication services across
multiple servers.

3S/400 Configurations
=====================

While parameters can be tuned lower to save substantial memory, this may
also significantly affect performance.  The 70 KB of additional code
size in 1.3 means that effectively 2 services that fit in a 3S/200 will
NOT fit in a 3S/400.

Therefore, typical configurations for a 3S/400 are:

.br;- File/Print, Name, Start, Backup (Pre-configured for maximum
performance)
.br;- File/Print, Name, Backup, Mail
.br;- File/Print, Name, Backup, Mail and Start or Locator (if the
parameters are tuned to the minimums.   Performance is affected)
.br;- File/Print, Name, Route, Mail
.br;- File/Print, Name, Backup, Start

The shipped, pre-configured services (File/Print, Name, Back-up and
Start) have been optimized for maximum performance.  When they are
loaded there is approximately 100 KB available for other services.

To load Locator or Route/Remote/NetConnect (R/R/Nc) the
parameters will not have to be reduced.  To load Mail, however,
the parameters will have to be reduced slightly.

If Backup is not required, then approximately 170 KB is available for
additional services.   Either Mail and Locator or R/R/Nc and Locator
will fit in 170 KB, however the combination of the 3 services, Mail +
Locator + R/R/Nc, WILL NOT fit.

In the long run, we are looking for ways to allow more 3+
services to fit on a single 3S/400.  We will keep you posted on
our progress.  3+Open will eliminate the DOS memory limitations,
thereby allowing more services per server.


.br;What Changed
.br;============

Most of the services did not change in size.  A few like CIOSYS even
decreased in size.   The major memory changes come from the following:

- Base Memory increased by approximately 35 KB.   15 KB was in the
BIOS code for better SCSI performance and 20 KB is used in ETH
buffering to improve packet buffering off/on the network.

- Share increased by approximately 50 KB.  33 KB was because of HIGHER
parameter settings for more users and better performance.   The code
increased 17 KB for powerfail and better messaging.

- Name service code increased 12 KB for powerfail and installation
changes to recognize another name service on the same network during
Quick Install.

- All other services and drivers increased a total of 10 KB for
performance, bug fixes, powerfail support, new installation, etc.

- Other services, such as Mail, Route, Start, etc did not change in
size.

As you can see the individual changes were small relative to the
new features and vastly improved performance that was realized.


Memory Map for 3S/200 and 3S/400 (Typical Configurations)
================================

The following are typical sizes, with parameters as set from the
factory.   Adding the services together gives a rule-of-thumb for the
services that will fit.   Required/typical are: Base + CIOSYS + Share +
Optional services = Total memory required.  (Remember: Parameters
settings per service can substantially affect the numbers given below.)


   Service                            3S/200 1.2.1     3S/400 1.3
   -------                            ------------     ----------

   Base Memory (DOS,Drivers,Buffers)  208 KB           253 KB
   CIOSYS                              80               89
   Share (File/Print)                 140              160
   Name                               131              143
   Locator                             36               36
   Start                               36               36
   Mail                               124              121
   Route (incl ACP.SYS)                78               78
   Remote      "                       78               78
   NetConnect                          45               45
   Backup                              75               71
   MacFS                               73               73(1.3.1)

(4/1/88)
