Systems Programming for 8 Yearolds 588

there was an iucv emulation done for mvs at one time.

the early mainframe tcp-ip product was done in pascal-vs on vm370; it used iucv to communicate between the ip network processing address space and various user application address space. the normal implementation had been clocked consuming a whole 3090 processor getting 44kbytes-sec.

i added rfc1044 support

to the product and in tuning tests at cray research between a cray and a 4341-clone it was getting 1mbyte-sec using only modest 4341 cpu (i.e. it was hardware limited by the 4341 channel interface) ... possibly 20 times the thruput for maybe 1-50th the cpu.

the base implementation was later ported to mvs (in part) by including an iucv emulation layer in mvs.

the communication division had been butterting that lu6.2 was significantly more efficient and higher thruput than tcp-ip ... and eventually they commisioned a contractor to do a vtam-based tcp-ip product implementation (to replace the iucv-based implementation ported from vm).

The initial tests resulted in the implementation being sent back to the contractor when tcp-ip showed significantly better thruput than lu6.2 (and so obviously there had to be significant bugs in the implementation that needed fixing ... or otherwise it couldn't have better thruput than lu6.2).

--