[net.micro] Buffered Downloads

ABN.ISCAMS%usc-isid@sri-unix.UUCP (10/08/83)

Problem:  When hanging a micro off a network or mainframe via a modem
and telephone line, I often want to download text or data (mostly text)
to a disk.  Unfortunately some networks and mainframes do NOT have a
compatible file transferral program, or I don't want to write my end of
one that'll work with what the mainframe does have.

I know about PIPMODEM and have successfully used it to download files,
breaking up large files in an editor as necessary to download a chunk
at a time (so as not to overload PIPMODEM's buffer and lose data as PIPMODEM
pauses to write its buffer to disk).  (Yeah, that happens big time when
there's a delay between PIPMODEM's ^S and the network's halting the
text output -- quite routine off my TAC here at Bragg.)

I know about the Christensen MODEM protocols, but haven't found the
equivalent on the ARPAnet that'll control my TAC/IMP and allow for that
doggoned delay.

Sure, I could kludge up something that would write to buffer; when full,
send a ^S; keep accepting and storing data until it someday stops; write
buffer to disk; clear buffer; move overflow to bottom of buffer; ^Q to
get text flowing again; etc., etc., but I ain't so very good in Assembler
yet that such an exercise is a cause for rejoicing.

Anybody know of a nice little program out there (CP/M, 8080) that does
such fancy bufferizing?

My TAC's terminal protocols permit flagging "TERMINAL PAUSE ON END-OF-PAGE",
and it dependably and immediately halts after a screenful of data; and
then dependably and immediately commences scrolling new data on transmittal
of a ^Q; so I can work with that just fine.  I just need that fancy buffer
overflow bit.

This might be useful to others that just want a down and dirty, no error
trapping, download full speed, program that'll trap scrolling text and
write to a disk.  I'll summarize if I get any answers from you all out in
NetLand, or if I break down and do it myself.

Thanks in advance.

David Kirschbaum

w8sdz%brl@sri-unix.UUCP (10/09/83)

From:      Keith Petersen <w8sdz@brl>

MDM712 does what you want.  In the ASCII capture mode when the buffer
gets full it issues a ^S and then accepts up to 128 more characters
before writing to the disk.  This is detailed in MDM712.DOC.  This
should be more than enough to compensate for the delays you mentioned.
Be sure your TAC's flow control is turned on AT THE TAC - not at the
distant host.  This is done with the @F O S (flow output start)
command to the TAC.  On all TACs I've tried so far, it's almost
instantanous response to the ^S and ^Q I send.  MDM712 and it's
associated files are available on SIMTEL20 in the MICRO:<MC.MODEM7>
directory.
--Keith

ron%brl-vgr@sri-unix.UUCP (10/11/83)

From:      Ron Natalie <ron@brl-vgr>

You can get the TAC to control the text flow immedialtely by saying

	@f o s

The control-q's and s's never even get sent to the remote machine.