Command Input IOP Description
The IOP command allows you to read, write, or format any of the supported disk or tape devices.
When invoked, this command goes into an interactive mode, prompting you for all the parameters necessary to carry out the command. You may change the displayed value by typing a new value, followed by the Return key. To leave the field unchanged, press the Return key without typing a new value.
You may also enter a special character, either at the prompt or after typing new data, for scrolling through the fields. The special characters are:
The disk SYSCALL functions (trap routines) are used by IOP to access the specified disk or tape (refer to Chapter 5, System Calls).
A device probe with entry into the device descriptor table is done whenever a specified device is accessed via IOP.
V or v Open the next field. This is the default, and remains in effect until changed by entering one of the other special characters.
^ Back up and open the previous field
= Re-open the same field
. Terminate the IOP command, and return control to the debugger
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descriptor table with the pertinent data. After an entry has been made, the next time a probe is done it simply returns with the message device present (pointer to the device descriptor).
Initially (after a cold reset), all the parameters used by IOP are set to certain default values. However, any new values entered are saved and are displayed the next time that the IOP command is invoked.
The following prompts appear (some prompts are device-dependent):
Controller LUN =00?
The Logical Unit Number (LUN) of the controller to access Device LUN =00?
The LUN of the device to access Read/Write/Format =R?
The command function:
Memory Address =00003000?
The starting address for the memory block to be accessed. For disk read operations, data is written starting at this location. For disk write operations, data is read starting at this location.
R Read blocks of data from the selected device into memory W Writes blocks of data from memory to the selected device F
!
Caution
Formats the selected device;
If you start the IOP format procedure, it must be allowed to complete (PPC1Bug> prompt returns) or else the disk drive may be totally disabled.
This format procedure may take as long as half an hour.
For disk devices, either a track or the whole disk can be selected by a subsequent field. This option only applies to SCSI Direct Access devices (type $00). When the format operation is selected, the Flag Byte prompt is displayed. A flag byte of $08 specifies to ignore the grown defect list when formatting. A flag byte of $00 specifies not to ignore the grown defect list when formatting.
Debugger Commands
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Starting Block =00000000?
The starting disk block number to access. For disk read operations, data is read starting at this block. For disk write operations, data is written starting at this block. For disk track format operations, the track that contains this block is formatted.
Number of Blocks =0002?
The number of data blocks to be transferred on a read or write operation.
Address Modifier =00?
Note Changing this Address Modifier parameter works for the MVME160x series modules only.
Track/Disk =T (T/D)?
File Number =0000?
The starting file number to access (for streaming tape devices) T Format a disk track
D Format the entire disk
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Flag Byte =00?
The flag byte is used to specify variations of the same command, and to receive special status information. Bits 0 through 3 are used as command bits; bits 4 through 7 are used as status bits. The following bits are defined for streaming tape read and write operations.
Retension/Erase =R (R/E)?
After all the required parameters are entered, the disk access is initiated. If an error occurs, an error status word is displayed. Refer to Appendix F for an explanation of any error status codes that are returned.
Bit 7 Filemark flag. If 1, a filemark was detected at the end of the last operation.
Bit 3 Disk formatting. It is ignored on tape operations.
Bit 2 Reset Controller Flag. If 1, a controller reset will take place if possible before the requested operation takes place.
Bit 1 Ignore File Number (IFN) flag. If 0, the file number field is used to position the tape before any reads or writes are done. If 1, the file number field is ignored, and reads or writes start at the present tape position.
Bit 0 End of File flag. If 0, reads or writes are done until the specified block count is exhausted. If 1, reads are done until the count is exhausted or until a filemark is found. If 1, writes are terminated with a filemark.
R Retension tape when a format operation is scheduled E Erase and retension tape when a format operation is
scheduled
Debugger Commands
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Examples
Example 1: Read 25 blocks starting at block 370 from device 2 of controller 0 into memory beginning at address $50000.
PPC1-Bug>IOP <Return>
Controller LUN =00? <Return>
Device LUN =00? 2 <Return>
Read/Write/Format=R? <Return>
Memory Address =00003000? 50000 <Return>
Starting Block =00000000? &370 <Return>
Number of Blocks =0002? &25 <Return>
Address Modifier =00? <Return>
PPC1-Bug>
Example 2: Write 14 blocks starting at memory location $7000 to file 6 of device 0, controller 4. Append a filemark at the end of the file.
PPC1-Bug>IOP <Return>
Controller LUN =00? 4 <Return>
Device LUN =02? 0 <Return>
Read/Write/Format=R? W <Return>
Memory Address =00050000? 7000 <Return>
File Number =00000172? 6 <Return>
Number of Blocks =0019? E <Return>
Flag Byte =00? %01 <Return>
Address Modifier =00? <Return>
PPC1-Bug>
Example 3: Format the specified device with the option not to ignore the grown defect list.
PPC1-Bug>IOP
Controller LUN =00? <Return>
Device LUN =00? <Return>
Read/Write/Format =R? F <Return>
Starting Block =00000000? <Return>
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Example 4: Format the specified device with the option to ignore the grown defect list.
PPC1-Bug>IOP
Controller LUN =00? <Return>
Device LUN =00? <Return>
Read/Write/Format =R? F <Return>
Starting Block =00000000? <Return>
Track/Disk (T/D) =D? <Return>
Flag Byte =00? 8 <Return>
Address Modifier =00? <Return>
PPC1-Bug>
Debugger Commands