Browse Prior Art Database

IBM System/370 Channel Emulation

IP.com Disclosure Number: IPCOM000052252D
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 3 page(s) / 141K

Publishing Venue

IBM

Related People

Ballou, DC: AUTHOR [+2]

Abstract

Some I/O devices, such as the IBM 3203-5 Printer, were designed to attach to the IBM System/370 channel. In order to attach the IBM 3203 5 Printer to systems which do not have the S/370 channel interface, it is either necessary to design such an interface, design a new attachment for the printer, or emulate the System/370 channel interface. The S/370 channel interface was emulated in the IBM System/38 for the purpose of attaching the 3203-5 Printer. The 5/38, for example, has a channel 10 (Fig. 1) and an I/O controller (IOC) 20 which includes a microprocessor. An I/O adapter 30 is attached to IOC 20 and contains the microcode for the microprocessor in IOC 20. Adapter 30 also includes registers and drivers and receivers which are shown in greater detail in Fig. 2.

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IBM System/370 Channel Emulation

Some I/O devices, such as the IBM 3203-5 Printer, were designed to attach to the IBM System/370 channel. In order to attach the IBM 3203 5 Printer to systems which do not have the S/370 channel interface, it is either necessary to design such an interface, design a new attachment for the printer, or emulate the System/370 channel interface. The S/370 channel interface was emulated in the IBM System/38 for the purpose of attaching the 3203-5 Printer. The 5/38, for example, has a channel 10 (Fig. 1) and an I/O controller (IOC) 20 which includes a microprocessor. An I/O adapter 30 is attached to IOC 20 and contains the microcode for the microprocessor in IOC 20. Adapter 30 also includes registers and drivers and receivers which are shown in greater detail in Fig. 2.

The IOC 20 (Figs. 1 and 2) connects to read-only storage (ROS) modules 31 and 32 via module/chip select logic 33. The drivers 40 and receivers 45 connect to a tailgate box 50, (Fig. 1) which has the same interface lines as tailgate block 60 in printer 70. In this particular instance, two printers can be controlled by 5/38. The tailgate 80 of the second printer 90 is attached to tailgate 60 of printer
70.

Generally, there can be channel initiated sequences, control unit initiated sequences or data transfer sequences. Channel initiated sequences are used to send commands to the I/O device, whereas control unit initiated sequences are used to indicate that an I/O device want...