billdcat@crash.cts.com (William Mortimer) (12/21/90)
I've been experimenting with KERMIT-11 on our PDP-11/73, and have found that
it won't do the job I need it to fast enough.
Our machine is a PDP, and we need to transfer large binary files back and
forth between it and a PC. We've been using KERMIT on both machines, which
are hardwired together via RS232 cable attached to serial ports on both
machines. At 19,200 baud, it takes 12 minutes to transfer a 700 block
(354 kbyte) file. This is too long. I understand that the limitation may
not be in KERMIT, but in the RSTS operating system itself, but I'm not sure.
I have a few questions:
1) Can KERMIT be optimized so the transfer will take less time?
2) Can the machine's operating system be optimized in some manner so the
transfer will take less time.
3) Is there a better protocol that I can use under RSTS/E that will allow
faster transfers? IF so, where can I get the source code?
4) Is there another way to go in through a serial port that doesn't require
any additional hardware?
Please respond via e-mail if you can help me out. Thanks in advance!
billdcat@crash.cts.comterry@spcvxb.spc.edu (Terry Kennedy, Operations Mgr) (12/21/90)
In article <6437@crash.cts.com>, billdcat@crash.cts.com (William Mortimer) writes: [text moved] > Please respond via e-mail if you can help me out. Thanks in advance! I responded via mail as requested, but thought the information might be of general interest, so here it is: >1) Can KERMIT be optimized so the transfer will take less time? Yes - I'm working on a newer version of Kermit for RSTS. The current one is rather inefficient, especially on input - it runs the scheduler on every input character. You should use the longest packet size you can get. When the RSTS system is receiving, you may have to shorten the packet size to eliminate data loss. >2) Can the machine's operating system be optimized in some manner so the > transfer will take less time. Depends. If you are using a DZx11 or DLV11 interface, you are generating an interrupt per character sent. For sending from the PDP to the PC, using a DHx11 would be a big improvement. >3) Is there a better protocol that I can use under RSTS/E that will allow > faster transfers? IF so, where can I get the source code? I have a version of XMODEM in BASIC. I could send you that if you'd like to try it. >4) Is there another way to go in through a serial port that doesn't require > any additional hardware? Leaving out the serial port bit, the best way to go is to get DECnet/E on the PDP (software and Ethernet controller) and on the PC (likewise). You can get up to 14Kbytes/second that way. It's a bit costly, but if you need the speed, it's the best way. Terry Kennedy Operations Manager, Academic Computing terry@spcvxa.bitnet St. Peter's College, US terry@spcvxa.spc.edu (201) 915-9381
ripley@opal.cs.tu-berlin.de (Hans-Ch. Eckert) (12/23/90)
In article <6437@crash.cts.com> billdcat@crash.cts.com (William Mortimer) writes:
3) Is there a better protocol that I can use under RSTS/E that will allow
faster transfers? IF so, where can I get the source code?
A friend of mine has implemented the Xmodem-Protocol in assembler.
I'll try to get the sources if there's enough interest.
Greetings,
RIPLEY
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