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The Programmer's Guide to TRSDOS Version 6 - Tim Mann's Home ...

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considered as non loadable comment records. It is thus possible <strong>to</strong> "un-yank" a yanked<br />

patch; however, this feature is not implemented in the PATCH utility.<br />

8.4 ERROR MESSAGE DICTIONARY<br />

Any time a SuperVisor Call experiences a malfunction, it returns an error code <strong>to</strong> the<br />

caller. <strong>The</strong> error codes possible are in the range . <strong>The</strong> operating system associates<br />

a message string with each error code. Each string can be displayed or obtained via the<br />

@ERROR SuperVisor Call request. <strong>The</strong> words contained in the messages are s<strong>to</strong>red in an<br />

error dictionary which is in a system overlay. This section of the appendix is a<br />

compilation of those error code messages and associated meanings.<br />

Error 00: No error<br />

A return code of zero indicates that there is no error.<br />

Error 01: Parity error during header read<br />

During a read request, the sec<strong>to</strong>r ID FIELD could not be satisfac<strong>to</strong>rily read. Repeated<br />

failures would most likely indicate media or hardware failure.<br />

Error 02: Seek error during read<br />

During a read sec<strong>to</strong>r disk I/O request, a sec<strong>to</strong>r ID FIELD noting the requested cylinder<br />

was not located within the time period allotted by the controller. Either the cylinder is<br />

not formatted on the diskette, or the step rate designated is <strong>to</strong>o low a value for the<br />

hardware <strong>to</strong> properly respond.<br />

Error 03: Lost data during read<br />

During a read sec<strong>to</strong>r request, the CPU was late in accepting a byte from the FDC data<br />

register and subsequently lost one of the bytes from the sec<strong>to</strong>r. For more information,<br />

consult the reference manual for the floppy disk controller used in your disk controller.<br />

Error 04: Parity error during read<br />

During a read request, the FDC sensed a CRC error. Possible media failure would be<br />

indicated. <strong>The</strong> Drive hardware could also be at fault.<br />

Error 05: Data record not found during read<br />

A disk sec<strong>to</strong>r read request was generated with a sec<strong>to</strong>r number not found on the cylinder<br />

referenced.<br />

Error 06: Attempted <strong>to</strong> read system data record<br />

A read request for a sec<strong>to</strong>r located within the direc<strong>to</strong>ry cylinder was made without using<br />

the direc<strong>to</strong>ry read routines. Direc<strong>to</strong>ry cylinder sec<strong>to</strong>rs are written with a data address<br />

mark that differs from the data sec<strong>to</strong>rs data address mark. See chapter 4 and chapter 5<br />

for additional information concerning address marks.<br />

Error 07: Attempted <strong>to</strong> read locked/deleted data record<br />

This error indicates that a request was entered which required a system overlay that had<br />

been purged from the system disk.<br />

8-9

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