Browse Prior Art Database

Initial Program Loading Technique

IP.com Disclosure Number: IPCOM000080836D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Catron, BN: AUTHOR [+8]

Abstract

As shown, a read/write (R/W) memory 3 is connected in parallel with the read-only control store (ROS) 4. When the system is operating under control of ROS 4, an address formulated by instruction address register (IAR) 5 is transmitted to ROS 4 where an instruction is identified that is transmitted to processor 6. The output of processor 6 may proceed directly to initiate the next address in the IAR 5, or indirectly by communicating with one of a plurality of registers, not shown.

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Initial Program Loading Technique

As shown, a read/write (R/W) memory 3 is connected in parallel with the read-only control store (ROS) 4. When the system is operating under control of ROS 4, an address formulated by instruction address register (IAR) 5 is transmitted to ROS 4 where an instruction is identified that is transmitted to processor 6. The output of processor 6 may proceed directly to initiate the next address in the IAR 5, or indirectly by communicating with one of a plurality of registers, not shown.

When the program seeks to address a location in the R/W memory 3, a linker code (a section of ROS control store 4 which controls IPL operation) at a predetermined address in ROS 4 causes the latter to be group selected using register 7 which, through a signal on group select line 8, causes the address from IAR 5 to be directed to R/W memory 3 by switching circuit 9.

To effect an initial program load (IPL) of R/W control store 3, the linker code turns on the IPL bit which is a signal on line 10.

This causes data read off disk drive 11 onto line 12 communicating with buffer 13 to also be connected to R/W memory via line 14. Accordingly, data read from the disk on drive 11 and transmitted through attachment 15 to buffer 13 on a cycle steal basis, is also transmitted to R/W control store 3. The fact that the use of the buffer data path is used for the IPL function causing the same data to be placed in buffer 13 is not significant, since following the IPL ope...