The following message is a courtesy copy of an article that has been posted to bit.listserv.ibm-main,alt.folklore.computers as well.
[EMAIL PROTECTED] (Ted MacNEIL) writes: > It's not just z/OS UNIX. > The first implementation of TCP/IP on OS/390 was a port from VM. > And, it was a pig until they decided to re-implement by starting from > scratch using z/OS UNIX (circa 2.7). there was two issues ... the base was implemented in vs/pascal on on 3090 (under vm) it got about 44kbytes/sec thruput and consumed nearly whole 3090 processor. i did the support for rfc 1044 http://www.garlic.com/~lynn/subnetwork.html#1044 and in some tuning tests at cray research ... got 1mbyte/sec (channel media) thruput between 4341 clone and cray machine ... using only very modest amount of the 4341 ... about 25 times the bytes moved for maybe 1/30th the pathlength ... say nearly three orders of magnitude improvement in bytes/mip thruput the initial port to os ... kept the base vm tcp/ip code unchanged and implemented a cut-down vm emulation underneath (just enuf to run the tcp/ip code) ... which further aggrevated the poor tcp/ip thruput there was then a tcp/ip implementation done "in vtam" that had been outsourced to subcontractor. the folklore is that initial version delivered had tcp with higher thruput than lu6.2 and the subcontractor was told that everybody knows that lu6.2 has much higher thruput (than tcp/ip) and therefor the tcp/ip implementation must be incorrect ... and only a "correct" implementation was going to be accepted. misc. past references to folklore about the vtam-based implementation for tcp/ip http://www.garlic.com/~lynn/2000b.html#79 "Database" term ok for plain files? http://www.garlic.com/~lynn/2000c.html#58 Disincentives for MVS & future of MVS systems programmers http://www.garlic.com/~lynn/2002k.html#19 Vnet : Unbelievable http://www.garlic.com/~lynn/2002q.html#27 Beyond 8+3 http://www.garlic.com/~lynn/2003j.html#2 Fix the shuttle or fly it unmanned http://www.garlic.com/~lynn/2004e.html#35 The attack of the killer mainframes http://www.garlic.com/~lynn/2005h.html#43 Systems Programming for 8 Year-olds http://www.garlic.com/~lynn/2005p.html#15 DUMP Datasets and SMS http://www.garlic.com/~lynn/2005r.html#2 Intel strikes back with a parallel x86 design http://www.garlic.com/~lynn/2006f.html#13 Barbaras (mini-)rant http://www.garlic.com/~lynn/2006l.html#53 Mainframe Linux Mythbusting (Was: Using Java in batch on z/OS?) http://www.garlic.com/~lynn/2006w.html#29 Descriptive term for reentrant program that nonetheless is http://www.garlic.com/~lynn/2007h.html#8 whiny question: Why won't z/OS support the HMC 3270 emulator i had a project i called hsdt (high-speed data transport) http://www.garlic.com/~lynn/subnetwork.html#hsdt that would periodically run into contention with the communication group. among other things, had deployed backbone connected to the internal network http://www.garlic.com/~lynn/subnetwork.html#internalnet that had T1 (and higher speed) terrestrial and satellite links. recent post http://www.garlic.com/~lynn/2007p.html#64 mentioning business trip to the far east to visit a company that we were buying some hardware from. the friday before we left, somebody in raleigh had announced a new internal discussion group that was to use the following terminology references: low-speed <9.6kbits medium-speed 19.2kbits high-speed 56kbits very high-speed 1.5mbits on the wall of a conference room, the following monday on the other side of the pacific low-speed <20mbits medium-speed 100mbits high-speed 200-300mbits very high-speed >600mbits we had also been doing some work with NSF and various universities leading up to what was to be NSFNET backbone ... aka tcp/ip is the technology basis for the modern internet, nsfnet backbone is the operational basis for the modern internet and CIX is the business basis for the modern internet. some old email references from that period http://www.garlic.com/~lynn/lhwemail.html#nsfnet ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
