The 360/30, 360/40 and 360/50 had integrated channels, cycle stealing from the CPU microcode. The channel-control unit-device structure was very similar to that of the 7000 series and the 7030. When the S/360 came out, channel I/O was the norm, and Interrupts go back to the 1950s.
Small machines like the 650 and 1401 had simpler I/O, but I don't recall anything older than the PDP-11 that had memory-mapped I/O. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List [[email protected]] on behalf of Don Higgins [[email protected]] Sent: Sunday, December 20, 2020 11:39 AM To: [email protected] Subject: Re: S/360 emulation in PC/370 Shmuel, all Well it is true that 360 I/O involved a separate channel processor that shared memory with instruction processor, and it required handling interrupts to determine status of I/O request. Some computers just had byte I/O handled by instruction processor. Don Higgins [email protected] http://secure-web.cisco.com/1xAUxDqgvPF44m1hb5pk8WB6_Mt-vU7vWp0BsIpd2D_nHqNBP1s8uFPxQTSjPqzGtGnWmR4Tm6yPxidVQ6oqA-6JTmccm-W4jOPRABz5zd-349UbxW-Hox-YoxB-_WDGtxpxQBH0KrWFhYX1MP-broDYZXo-sXZxeXCffIsTKBg4PwroaEH4JBMm4PIQXXp2oRsQOLejxwpXOUm3CpEAL-2QF4qx4JX6il4rkW-beYcHpl-iWrRg9X64SsSi6GOErJe79krubr51Oj40bDlk2ZhyAzXcs_ReCijxKXaGONrcrOusmuySJMenci3iYZHFOtvXr8PR1LcxiAaY10T0ln0t7E88XM4iBPBB_G0Be2MyM0Vv5McVYTpoj_njCuqBdGkOPpX9d8OSo2TIMVcJ4BVaqTD6eV7HY-no8BH6Tw_Ei2dvMf2exSGM4dBCEi0Sx/http%3A%2F%2Fwww.donhiggins.org -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Seymour J Metz Sent: Sunday, December 20, 2020 10:58 AM To: [email protected] Subject: Re: S/360 emulation in PC/370 Any idea why Peter found S/360 I/O alien? I certainly thought that it was conventional when it came out. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List [[email protected]] on behalf of Don Higgins [[email protected]] Sent: Saturday, December 19, 2020 10:13 AM To: [email protected] Subject: Re: S/360 emulation in PC/370 All Back in 1980-1981 I wrote PC/370 first in z80 assembler and then ported it to 8086/8087 in 1995. The last shareware release was in 1989 and then I sold all rights to Micro Focus in 1993 before I went to work for them as system software engineer for 9 years before retiring. PC/370 ran on MSDOS and included 360 assembler, linker, and emulator. The coding was relatively easy in z80 because both architectures were byte oriented. As for I/O, I did not depend on SIO and CCW's. Since it ran under MSDOS, I just used user SVC's to route I/O between host I/O and 360 svcs. Here is link to PC/370 up to z390 history: http://secure-web.cisco.com/1TKNAMNAtRkOczWfRUdTeydpUzZfPXpVJoL2TSv8xWtKE3ME ebnhb9QaLt5zx2A5xz15e9CZ3-IvY1tzUOttoEEp6Ty-zVdoccV_sVE31r3N-F2gYkuXhJCyFM2d 8GQJER7vc0QtHWQcJJcJ9p8fA99_VoCYRtZQ4ptAKG-TmV5j132DSSl48EkhipD-ZYNlYuX7MxJY TW7ijOUY_EgexSg1aI4x8Y7GqBdMlnLfibT8lKMtTIuaBRisEMwfjEDB00g__1juwWmwsbKlxnAr 1jVVb2zRQpOaEmzknv_N-fMp-VFcz8bwNJgKdraXVSBZImOHOexP2ETXAsDWqI45VLbDm6QGkIOQ zXEW7d47qrFG749fTTMNKUGZj6xwzLoVHQ9LrcY9ioFg0A4pPyvnMy5QKHggJwNkYQWGYoaiTW2y e17BE500m-Sr6MfR3cIO4/http%3A%2F%2Fdonhiggins.org%2Fpc370.htm Don Higgins <mailto:[email protected]> [email protected]
