Register Alarm Bit As End-Of-Write Signal
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
When a frame of data is written from a host processor to a workstation via an IBM 3278/79 Emulation Adapter (EA) that is connected to a IBM 3274/6 Control Unit (CU) in a Control Unit Terminal (CUT) mode, the frame appears as a series of blocks at the workstation software randomly at speeds based on the CU speed. There is no way of knowing when the last of the blocks has arrived at the device buffer. This does not present a problem for displayable frames because each piece generates an interrupt when it arrives, is displayed, and the CU speeds are fast enough to accommodate operator needs. However, for "Host Upload/Download" (HUD) data frames, there is a problem in that the workstation software receiving the blocks making up a frame can get ahead of the CU, resulting in lost data on the workstation to host link.