IBM 2790 Manual page 51

Error data is transferred automatically whenever this
message assembly area becomes full. The 'D7' request
is provided to enable the CE to purge this area, thereby
ensuring that all 2715 error recording accumulated to a
certain point in time has been transferred to the Sys-
j tem/360 error file prior to running EREP (Environment
I Record Edit and Print).
• Request Format
System/360— Standard format: no additional data required.
CE Panel-Standard format: no additional data required.
• Response Format
Response:
| SOH % E XSTX [Text] ETX
Text consists of a format byte (X'08'), two blanks, two
identification bytes (user specified), and from one to five
blocks of error data. Each block contains day and time
stamp bytes) and statistics for seven errors (28 bytes).
(7
Message length depends on the number of error blocks
included: L = 5 + 35N, where N = the number of blocks.
X'D8'—Reinitialize 2715 Disk
The 2715 does not re-use disk for data storage. Therefore,
to reduce the seek time between data read and writes, and
to prevent completely filling up the disk, the 2715 disk must
| be periodically re-initialized (see Figure 29).
To prevent overrunning the disk, the 2715 checks for a
threshold of 64 available sectors. When this threshold is
exceeded, the 2715 will:
a. Generate an X'FD' message (unsolicited 2715
response) informing System/360. The first data
byte is X'F 2 \
b. Initiate a "stop 2790 input" control request.
Unique Sequences
S/360
1. Set Read deferred data mode X 'C 5 '------- ► Execute
2. (a) Stop 2790 Input X 'C ó '----------------- ► Stop Loop
(b) Read Data ^
3. Read Response ^
4. Read Data ^ -----
5. Read Response ^ ------------------------------- Response X'C5' to Def Data
6. (a) Reinitialize 2715 D isk X 'D 8 '-------- ► Initialize Disk
(b) Read Response ^ --------------------------Send X'D8' Response
(c) Set Restart number Log to Zero
7. Set Day (Optional) X'E2' ■ "
8. (a) Restore 2790 Input X'C7' ------------- ► Start Loop
(b) Read Response ^ --------------------------Send X 'C 7 ' Response •
• Figure 29. Read Deferred Data and Reinitialize Disk Sequence
2715
— ......... Send Data
Response X'Có' to Stop Loop
Send Data
^ Execute
• Function— Checks for the proper preconditioning of the
2715, and, if correct, will re-initialize the disk.
Required re-initialization sequence:
a. 2790 input must be stopped (X'C
b. 2715 must be empty of all data; i.e., System/360
must have set 2715 in read deferred data mode
(X'C5' executed) and received the X'C5' response
indicating the 2715 is empty of data.
c. System/360 sends X'D
• Request Format
System/360 only-Standard format.
• Response Format
Standard format:
a. Positive— disk re-initialized.
b. Negative— proper re-initialization sequence not
followed.
X'D9'— On-Line Core Dump
• Function— Prints out selected 2715 core storage posi­
tions in a line of hexadecimal characters on the 2740.
The request is made by the 2740 and the response is
made to the 2740.
• Request Format
The following sequence from the 2740 enters the
request:
Line Bid— R— Starting Address— Byte Count— EOT
The starting address is the hexadecimal representation
of the first core position to print out. The byte count
is the hexadecimal representation of the number of
bytes to print out (X'00'— X'32'). If no byte count is
entered, the 2715 assumes an X'32' count.
• Response Format
The response is a line of hexadecimal characters printed
on the 2740.
X 'E2'— Set Work Day Number
• Function— Provides for setting the work day number.
This number is included in the message header of all
data transferred to the System/360 or disk.
' executed).
6
' request.
8
Transmission Control Unit 51