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This is a modified version of the Internet RFC suitable for machine-translating. Original version is available here: RFC227

Network Working Group                                         J. Heafner
Request for Comments: 227                                     E. Harslem
NIC: 7631                                             September 17, 1971
Updates: RFC 113


The attached memo indicates data rates typical of our use of RJS at UCLA CCN. Earlier timing tests (similar but more detailed) with UCSB showed that most of the time was lost because of: (1) channel contention with our disk drive access; (2) our NCP runs at a higher priority than batch jobs but lower than text editing and interactive graphics; (3) OS interrupt handling is very slow on both ends; (4) spooling time of the remote system.


TO: John Heafner FROM: Bob Hoffman COPIES: Bob Mobley, Herb Shukiar

Here are some of the transmission rates I have noted over the network between Rand and UCLA. These were all taken at night when little else was happening on our 65.


# Cards Blocksize (bytes) Time (secs) Rate (bits/secs)
642 80 50 8218 375 80 30 8000 509 800 20 16288


For all figures below, the receiving file has blocksize of 1330 bytes, and each line is assumed to contain 100 bytes. This last assumption is fairly accurate, since most of the lines were from PL/I for which this is a very good number. Thus, for each rate, the number of bytes is the # Lines * 100.
   # Lines          Time (secs)      Rate (bits/secs)
      4900              200             19600
872 47 14843
3900 185 16865

Heafner & Harslem [Page 1]

RFC 227             DATA TRANSFER RATES (RAND/UCLA)       September 1971
As you can see from the send figures, blocking makes about a 2:1 difference. Memory also recalls a 2 or 3 to 1 advantage for blocking on receive when we were getting unblocked files from UCSB.


[This RFC was put into machine readable form for entry]
[into the online RFC archives by Kelly Tardif, Viagénie 10/99]

Heafner & Harslem [Page 2]

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