🚀 go-pugleaf

From article <3782@accuvax.nwu.edu>, by dave@acns.nwu.edu:
> From:     David Wenger <dave@acns.nwu.edu>
> 
> 	While this is rather after the issue has passed:
> 
> In terms of Mac-to-Mac file transfers, although not ftp related, I
> have had excellent experiences with Claris' Public Folder.  It is a
> simple, easy method to transfer files between Macs on any sort of
> network.  I have successfully transferred files between zones linked a
> wide variety of fashions, frequently with better performance than that
> achieved by many other network utilities.  On a direct phone net
> connection, I have seen Public Folder do large file transfers at
> somewhere in the range of 150 K/sec.  Appletalk itself is only rated
> for 230 K/sec.  Over Macs connected by Ethernet I have not done many
> large transfers, but it is faster.  When I am carbon copying hard
> drives, I simple install Public Folder on both of them and let it run.
> I have seen it transfer chock full 80 Meg hard drives in 15 minutes.
>

  Ok, I think something needs to be cleared up here about the performance
of LocalTalk (the hardware, as opposed to AppleTalk, the protocols). First
the maximum speed of LocalTalk is 230Kbps, or 230000 BITS per second. Divide
that by 8 and you get the theoretical maximum throughput of 28.75Kbytes/s.
This of course assumes (erroneously) no protocol overhead. Now about backing
up the 80 meg "chock full" hard disk over phonenet (which is basically the
same as LocalTalk cabling, but somewhat different [better]) in 15 minutes:
By my calculations, the BEST you could hope for with a 70 meg transfer is
230000/8/1024/1024 (bits/sec div bits/byte div bytes/"K" div "k"/"meg" =
meg/second) 0.0274 MB/s with impossibly good comditions. Now invert that,
and you get 36.5 secs/MB. Times 70MB = 2553 secs, which is 42.6 minutes. Now
if you want to add realism to this figure, you'd have to figure in the network
traffic, since everyone has to share that bandwidth, and you get a not so
great backup time, although I admit it is DARN convenient! If you backup
something in 15 minutes, the biggest that it could be is under 24MB. Now,
if you could set this up to happen at, say, the middle of the night or lunch,
then who cares? It gets done. 
  Unfortunately (for me), Ethernet comes in all sorts of capacities, but all
that I know of are orders of magnitude better than LocalTalk. I mentioned
earlier that 230Kbps is the best LocalTalk/PhoneNet can do. There ARE pro-
ducts available that, when used with faster machines like the Mac II's, can
transfer data faster, but they are not the most realiable solution, unless
everyone has a fast machine. Better is EtherTalk, which is still many times
faster than any LocalTalk setup. (If I remember correctly, average Ethernet
speeds are in the 1-10Mbps range [where LocalTalk is at .23 Mbps].)
  PhoneNet has many advantages over LocalTalk cabling. It is cheaper, more
reliable (as far as coming unplugged accidently), and has better electrical
transmission properties than LocalTalk. LocalTalk is an absolutely horrid
cabling for a network, but that's much more technical. Moral: avoid LocalTalk
like the plague, if you can.
  Sorry this turned out so long, but I hate to give anyone the impression 
that LocalTalk is anything but a dirt cheap networking solution. Just keep
that <30K (bytes) per second in mind next time you see a few Macs networked
together with LocalTalk. With a modest six people on the net, that's <5K/s
for each. Now if they all try to start an application or load a big file at
the same time, they have a wait coming to them. I can't recall off the top
of my head, but does anyone know the transfer rate for a floppy drive,
including SS, DS, and HD flavors? Just curious, have to hack up a test
program....

Robert Minich
Oklahoma State University
minich@a.cs.okstate.edu

Disclaimer, "I had nothing to do with President Campbell's allowing football
players, who failed to meet the minimum requirements for enrollment, to go
ahead and enroll anyways. (Is a 2.0 too much?)"

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