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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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