Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!.UUCP!A.LAWRENCE From: A.LAWRENCE@.UUCP ("psuvax1.psu.edu a.lawrence") Newsgroups: comp.lang.asm370 Subject: Re: IPL Message-ID: <9003271958.AA21995@lilac.berkeley.edu> Date: 27 Mar 90 05:03:07 GMT Sender: daemon@ucbvax.BERKELEY.EDU Reply-To: IBM 370 Assembly Programming Discussion List Distribution: inet Organization: The Internet Lines: 24 PROHVK38@TREARN.BITNET (orhan): > Does anybody know IPL RECORD format ? > This record is first record in any sub system device. The standard IPL record on any System\370 device is 24 bytes. It consists of 2 CCW's (channel command words) followed by a PSW (Program Status Word). The IPL function issues a read (X'02') command to the specified device into location zero (sorry I don't remember the length), a TIC (transfer in channel) to location zero to execute the CCW's just read. When the channel program terminates, the PSW is loaded from location X'000010'. For a complete description of the process, refer to the "Princples of Operation" manual for your particular computer. --- On a clear disk you can seek forever. ------------------------------------------------------------------------- Andrew Lawrence | alawrenc@sobmips.sobeco.UUCP Informaticien Conseil | {attcan,mcgill-vision}!sobeco!sobmips!alawrenc 3462 Jeanne-Mance, #1 | Montreal, Que CANADA | Voice (514) 281-5196