Very Computer

Can any one tell me what the difference between AFPS & NFS???
  Why might I want one over the other.  Which is faster or more reliable?

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Joe DeBiso
Plantrol Systems, Ltd.

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Definitely not an apples to apples question.  These are 2
very separate and distinct products.  I can't tell you why
you would want one over the other as that depends on what
you are trying to accomplish.  Speed and reliability
doesn't really apply here.  Let me give you my
perspective.

NFS: This is simply the ability to mount filesystems over
the network.  NFS is included as part of the 5.0.X
products and all you need do is install NFS Runtime as one
of the protocols in your network configuration.  Once
configured, you then have the ability to mount remote
filesystems to your local host.  As an example:

        mount -f fstype remote server/fsname /local mntdir
                        - AS IN -
        mount -f LMCFS win95/cdrive /mnt
This example allows me to mount the root directory of
drive C on a remote Windows95 client onto the mnt
directory of my local server.  Now I can access the files
for reading/writing/copying, etc.  Speed is dependent on
the network operation as the packets travel over the
network connection.  Very reliable. SCO will support
various file system types for Network FileSystem (nfs)
mounting.

AFPS: This is a product that allows you to set up a NT
network environment using your SCO server as either a
primary or backup domain controller.  In essence, you will
have the equivalent of an NT network without having to
have an NT server (although it will work in conjunction
with NT servers).  When installed, your WIN95, WFW, DOS
and NT Clients can all share printers, directories, files
between themselves or with the SCO server.  There is
administrative overhead of setting up users, shares,
domains, priveleges, etc.  Very reliable and speed is
again a function of the network.  AFPS is available as a
free single user version or you can purchase multi-user
versions.

I would suggest visiting SCO's web site for more
information on AFPS as there isn't time or space to give a
complete description of its capabilities and functions.

I hope this gives you some idea of the differences and
capabilities of each.

Quote:

>Definitely not an apples to apples question.  These are 2
>very separate and distinct products.  I can't tell you why
>you would want one over the other as that depends on what
>you are trying to accomplish.  Speed and reliability
>doesn't really apply here.  Let me give you my
>perspective.

Hi !

This question is the favorite one from many of our
customers ! I'll try to summaryze the answers I
usually provide them with (I apologize in advance
for any mistake I'll do - as you can see from the sign,
I'm from Italy and English is not my native language).

1) How much do you want to pay ?
Keep in mind that if you're connecting a bunch of machines
equipped with Win4Work, Win95 & NT, then
the network is provided as part of the operating system
itself so you don't have to pay anything for the Windows
side. OTOS, if you want to connect a UNIX machine to such
a network, then I'll need AF&PS (which is not so cheap)
for SCO OS5 or Lan Manager/X for SCO UNIX 3.2v4.2.

2) Are you planning a local LAN ?
If your answer is yes, then consider that MS-NET (the
procotol which powers AF&PS) is very fast & flexible when
used in small networks and it's very easy to setup & configure.
On the other side, NetBeui (the core protocol for MS-NET)
is unable to cross routers so you'll be unable to spread
your network across 'em (you can bypass this problem by
using NetBIOS, which is basically NetBEUI over TCP/IP.

3) Do you plan to extend your LAN to the Internet ?
If your answer is yes, then TCP/IP+NFS rule. Also, consider
that almost every OS has its own porting of TCP/IP whereas
AF&PS is specifically written for SCO OSes.

4) Realiability vs speed
MS-NET is faster than NFS but NFS is more reliable. The
reason ? MS-NET uses asynch. writes when it has to write
data on the server disk; this means that the written data
are first stored in the RAM cache which, after a while,
is actually written to the server disk. NFS (by default)
uses synch. writes; when you're notified that the data
are written to the disk, they're on the magnetic media
indeed. So, while MS-NET is faster because it first stores
the data in RAM before flushing 'em to disk, NFS is more
reliable because it stores the info directly to the disk.
However, in SCO OS5 there's an NFS related tunable
parameter which could be programmed in order to force it
to use the RAM cache. If my memory serves me well, there
are 3 possible states; 1) synch writes (the old style NFS
behaviour) 2) mixed mode (it caches some data to RAM)
3) full cache use (like MS-NET).

5) Setup & configuration
MS-NET is very easy to setup and administer; when configuring
an AF&PS machine, you have only to provide it with an unique
network name, a domain name and the role for which the server
has been assigned. After relinking & rebooting, your server
becomes automatically visible on the Lan, thus allowing the
client to establish their network connection "presto".
TCP/IP & NFS are a little bit complex to setup & administer;
you have to provide each machine with its own IP address,
subnet & broadcast mask (which involves a good background on
how to assign 'em) and so on. NFS services are easily
administered via the scoadmin interface, which has been
added starting with the release of OS5, even if you have to
pay great attention to a couple of files located on the server.

6) Services
AFAIK, MS-NET only allows you to share HDs & printers; once
it had a primitive terminal emulation program (VTP) but dunno
if this piece of software is widely used these days. OTOS,
TCP/IP offers a wide plethora or services, ranging from
terminal emulation to file transfer protocol, time synchronization,
remote backup, remote printing, network file sharing and so on.

So, at the end ; if you want to setup a LAN to basically
share HDs & printers, than AF&PS could be the right choice.
If you plan to extend your LAN to the 'Net or if you want
to take advantage of extended services in a etherog.
anvironment, that TCP/IP+NFS could be the choice.

Hope this helps !

P.S. = I don't want to start a flame war or a discussion if
       NFS is better than AF&PS so no flames, please ;->
       They're only my opinions !

Best,
Roberto
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