Chuck Forsberg: Difference between revisions

'''Charles Alton "Chuck" Forsberg''' (May 6, 1944 – September 24, 2015)<ref name="obit">{{cite web|url=http://www.anewtradition.com/obituaries/obituary/12060_Charles_Alton_Forsberg |title=Charles Alton Forsberg obituary |publisher=Anewtradition.com |date= |accessdate=October 10, 2015-10-10}}</ref>) developed two [[data transmission]] protocols popular for [[upload]]ing and [[download]]ing files from dial-up [[bulletin board system]]s in the 1990s. He received a [[Dvorak Awards|Dvorak Award for Excellence in Telecommunications]] in 1992 for developing [[ZMODEM]].<ref>{{cite web |url=http://www.citivu.com/dvorak/#1992 |title=Dvorak Awards |author=[[John C. Dvorak]] |accessdate=8 December 8, 2010 |url-status=dead |archiveurl=https://web.archive.org/web/20140306184406/http://www.citivu.com/dvorak/#1992 |archivedate=6 March 6, 2014 }}</ref> He was also the project engineer on the [[Tektronix 4010]]-series graphics terminals.

The widely adopted [[ZMODEM]] useduses a [[sliding window protocol]]. Rather than wait for positive acknowledgment after each block is sent, it sentsends blocks in rapid succession and resentresends unacknowledged blocks later. By avoiding delays due to [[latency (engineering)|latency]], the bandwidth usable for transmission more closely approached the [[bandwidth (computing)|bandwidth]] of the underlying link. ZMODEM could also resume interrupted transfers without retransmitting the already-received blocks. In addition to developing the protocol, Forsberg developed [[software]] for sending and receiving files using ZMODEM.

Forsberg then wrote a version, Zmodem G, which was for use over "guaranteed error free" communications lines, such as Ethernet or short serial-to-serial computer connections. This protocol waived the usual retransmission overhead, to send files as fast as possible.

Originally, he wrote a program for Unix called rbsb (receive batch / send batch) which used block 0 to transmit a file's name, and optionally date and time, since [[Ward Christensen]] designed [[Xmodem]] to start at block 1, leaving block 0 available. Christensen suggested Forsberg call his protocol [[Ymodem]] because it was "one better" than [[Xmodem]]. Forsberg created the program ''YAM'', which in traditional Unix nomenclature stood for ''Yet Another Modem'' after "Modem.asm" the original version of [[Xmodem]] released by Christensen in the CP/M User's group in 1977.

Forsberg most recently resided in [[Portland, Oregon]], prior to his death. He ran data transmission software company Omen Technology which he founded in 1984.<ref name="autogenerated1">{{cite web |url=http://www.omen.com/about.html |title=About Omen Technology |accessdate=2012-02-16 |url-status=bot: unknown |archiveurl=https://web.archive.org/web/20150915193210/http://www.omen.com/about.html |archivedate=September 15, 2015 }}</ref> He was an [[amateur radio operator]] (call sign WA7KGX)<ref>{{cite web | url = http://wireless2.fcc.gov/UlsApp/UlsSearch/license.jsp?licKey=862831 | title = Amateur License – WA7KGX – FORSBERG, CHARLES A | accessdate = 2012-02-16}}</ref> and a licensed aircraft pilot.<ref name="autogenerated1"/>