ephraim@wang.UUCP (pri=8 Ephraim Vishniac x76659 ms1459) (02/25/86)
With all this discussion in info-mac and net.micro.mac about the "real" speed of various terminal emulators, I decided to run a simple test. I transferred a large file from a Wang PC to a Mac and timed the transfer. The line speed was 19,200 bps. The machines were set for 8 data bits, no parity, 1 stop bit. The file was 174,080 bytes in MacBinary format. The sending program was "ic", a VT-100 emulator package, running off a 20meg winchester. The receiving program was MacTerminal 2.0, running on a HyperDrive. The transfer was timed with the Mac alarm clock, which stops updating while a transfer is in progress. Elapsed time for the transfer was 7:18 (438 seconds). 174080 bytes * 10 bits/byte / 438 seconds = 3974 bps. (10 bits per byte = 8 data bits + 1 start bit + 1 stop bit). Allowing 10% xmodem protocol overhead (a generous allowance) raises the line usage to about 4370 bps or 23%. I'm not impressed. Anyone care to try it with two Macs?
thomas@utah-gr.UUCP (Spencer W. Thomas) (02/27/86)
In article <765@wang.UUCP> ephraim@wang.UUCP (pri=8 Ephraim Vishniac x76659 ms1459) writes: >the line speed was 19,200 bps. Can your machine really sustain 19.2kbps output? Many can't. >174080 bytes * 10 bits/byte / 438 seconds = 3974 bps. > >Allowing 10% xmodem protocol overhead (a generous allowance) >raises the line usage to about 4370 bps or 23%. This about matches the performance I saw at 9600 baud from a Vax to a RamDisk. The Vax CAN sustain 9600, so I expect that this is about MacTerminal's maximum data rate. I'll try it at home (at 4800 baud) and see if it goes down any. -- =Spencer ({ihnp4,decvax}!utah-cs!thomas, thomas@utah-cs.ARPA)