ftp.wwiv.com/ftp.wwiv.com.zip/ftp.wwiv.com/pub/BBS/SBBS1B00.ZIP/DOCS.EXE/DOCS/MULTNODE.DOC

Text File | 1992-09-14 | 6KB | 109 lines

           Synchronet Multinode Documentation
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Synchronet Version 1b runs under DOS v3.0 or greater and SHARE (or NetWare).
A DOS process is required for each node on a Synchronet system. You can run
multiple nodes on one cpu with DOS multitaskers such as DESQview, Windows,
or OS/2 v2.0 or you can run one node per CPU and let the CPU's share the same
data on a common hard disk via Local Area Network (LAN).

LAN Method
~~~~~~~~~~
Using one CPU per node is by far the fastest (and possilby cheapest) way to
run multiple Synchronet nodes. Since Synchronet runs in 8086 real mode, any
IBM PC can run Synchronet with sufficient speed. The minimum equipment
necessary for each node would be a power supply, motherboard, at least 500k
free memory, a network interface card (NIC), floppy drive and controller (or
just a boot PROM for the NIC), and a modem. Some BIOS's require a video
controller and/or a keyboard as well, but they are not necessary for the
execution of Synchronet.

To link these computers together, you will need some form of networking
software. DOS based networks (Lantastic, NetWare Lite, CBIS Network O/S,
MainLAN etc.) are the cheapest and don't require a dedicated CPU as a file
server, but they lack the speed of a dedicated file server and network
operating system. The most popular Network Operating System (NOS) is Novell
NetWare. The disk performance on a dedicated NetWare file server is often
preferable over a local hard disk (especially on XT's) due to NetWare's high
speed file system and dedicated memory for intelligent disk caching. Synchronet
will run on any NOS that allows multiple CPU's running DOS to access data on a
common disk.

An alternative to using an individual computer for each node would be to use a
"computer on a card" board. Currently the most popular and reliable company
that produces these is Cubix Corporation. You can purchase a 4 XT board that
plugs straight into a NetWare file server bus slot for under $1500. You will
need a normal workstation for monitoring the nodes and performing local
maintenance, but you could make that workstation a node as well. So you can
have excellent performance with up to 21 nodes on just two computers (the
workstation and the file server). And external expansion buses are available,
each holding up to 12 cards (48 nodes) without adding any more individual
computers. You will need an external modem and serial cable for each node.


*** ATTENTION LAN USERS ***

Do not give ANY of the files associated with Synchronet a sharable file
attribute. Synchronet uses file and record locking to handle multiple
simultaneous file access requests and maintain data integrity. "Flagging"
a file "sharable" overrides these locking methods and will cause Synchronet
to corrupt your data in a multinode system.


Multitasker Method
~~~~~~~~~~~~~~~~~~
Any program that allows the simulataneous execution of multiple DOS programs
should be able to run multiple Synchronet nodes per CPU. To reliably and
efficiently run multiple DOS sessions on one CPU, you will probably need an
80386 CPU (the faster, the better), and at least 2 megabytes of memory
(the more, the better). Different multitaskers will have different hardware
requirements, but the common denominator seems to be an 80386 and extended
or expanded memory.

You will need a separate IRQ line and UART I/O address for each COM port in
the computer. If you wish Synchronet to always use BIOS calls for screen
output, you need to include the B parameter on the SBBS command line. Normally,
Synchronet uses direct video for block text which can conflict with some
multitaskers that manage a split screen for multiple DOS sessions.

Generally, the faster the machine, the more nodes you can run. But how many
for what kind of performance is not an easy question to answer. It depends
heavily on the multitasking software, modem speed, and hardware I/O. Under any
configuration, expect some amount of performance degradation when running
multiple nodes per CPU.


Is it Safe?
~~~~~~~~~~~
Many Sysops will worry how reliable the system is with multiple simultaneous
users. Rest assurred that Synchronet was designed from the ground up for
multiple simultaneous users. Data integrity and system fault tolerance is never
sacrificed when adding nodes to a Synchronet system.

Users can post on the same sub-board, e-mail the same user, download the same
file, run the same external program, perform virtually any system function
simultaneously. Note: External programs must support multiple simultaneous
users if the program has been configured for multiuser access from Synchronet.

Considerations and precautions have been taken where user data is concerned
to allow changes to the real-time database to take place immediately - even if
the user is online on a node other than the one that performed the data update.
Any security, configuration, or statistics changes made remotely will take
effect immediately.

The transfer section disallows simultaneous uploading of the same filename to
the same directory and prevents a file that is currently open (being downloaded
or just added to a user's batch download queue) from being moved, removed, or
edited while allowing simultaneous downloads.

As a general rule, no data files or records are allowed exact simultaneous
access if one of the nodes will modify the data. Simultaneous read only access
is allowed. Collisions (simultaneous write access requested of a file by two
or more nodes) are logged along with the retry count. There is a retry maximum
count (or time-out) that will deny access to the requesting node and log a
critical error for that node. This situation should not occur, but provisions
are made for it in case of hardware failure of a node with a file or record
open with write access.

/* End of MULTNODE.DOC */