Optional repairs are available for use with high capacity tapes which will provide the capability to write:

1. VME magnetic tape files in excess of 999999 blocks.

2. more than 9999 files to a VME tape.

Users should be aware that, with high capacity tapes, there are potential problems associated with the ISO standards and hence the VME standards which limit the number of data blocks in a file to 999999 and the number of files on a tape to 9999. This is due to the label formats which restrict these values to 6 and 4 printable characters respectively. The optional repairs itemized below enable VME tapes (i.e. non ISO) to extend beyond these limits but this contravenes the current standards and the following information (together with the special instructions in the repairs) must be carefully assessed to determine which set of repairs is required for your system.

Optional repair MM/K/0565

If optional repair MM/K/0565 is not applied, an attempt to exceed the block count of 999999 will fail with the Result Code 30954, MM_NO_SPACE_FOR_WRITE.

This Result Code will always be reported for an ISO tape exceeding the limit of 999999 even when the optional repair is applied.

Effect of the optional repair MM/K/0565 (without MM/K/0884): -

If more than 999999 blocks have been written to the file section then the block count field in the EOF1/EOV1 label will be filled with the printable characters of 6 asterisks.

Any attempt to append to the end of such a file section will be prevented with the Result Code 33444 (MM_FILE_SECTION_NOT_AVAILABLE).

No block count check can be made when the EOF1/EOV1 label is subsequently read but with VME tapes the resilience data will provide the necessary security against the (rare) possibility of missed blocks.

N.B. This solution contravenes the VME standards. Whilst some user will find this is acceptable, there will be others who will need to be aware if they have generated a non standard tape and will require additional repairs (detailed below) to be applied for notification of this situation, for example, if the tapes are to be processed by an alternative system that is not capable of processing this new format label.  

Optional repair MM/K/0884

MM/K/0884 (together with MM/K/0565) will enable the writing, processing and appending to a VME tape file with a block count in the range 999999<n<1573120575 by employing an alphanumeric count.

When deciding whether or not to apply this optional repair the following points must be considered:

•  This alphanumeric format contravenes the current VME standards and should not be utilised if the tapes are to be processed by an alternative system that is not capable of processing this new format label.

•  The block count field will remain in the standard format provided no more than 999999 blocks are written to the file.

Effect of the optional repair MM/K/0884 (with MM/K/0565):-

If more than 999999 blocks have been written to the file section then the block count field in the EOF1/EOV1 label will be filled with the printable characters in an alphanumeric format details of which are available within the ‘special instructions' section of repair MM/K/0884.

It will be possible to append to the end of such a file section within the limits specified above.

The value will be used for block count checking.  

Optional repair MM/K/0735

With the application of this optional repair, any tape that has been written with the block count of '******' (provided by MM/K/0565) or the alphanumeric block count (provided by MM/K/0884), will be blacked with a blacking code of 20. A message will be logged to the operator and user's job journal to record this tape blacking. 

This repair is strongly recommended for any users who are likely to inter-change tapes between sites as both formats contravene the VME standards. If a blacked tape is subsequently sent offsite for processing then the receiving site should be made aware of the changes to the labels.  

Optional repair MM/K/0829

MM/K/0829 will enable the number of files on a non ISO tape to be increased from the current maximum of 9999 to 1223055 by employing an alphanumeric file sequence count in the appropriate fields of the HDR1 and EOF1/EOV1 file labels.

When deciding whether or not to apply this optional repair the following points must be considered:

• This alphanumeric format contravenes the current VME standards and should not be utilised if the tapes are to be processed by an alternative system that is not capable of processing this new format label. Further details are available within the ‘special instructions' section of repair MM/K/0829.
• The file sequence field will remain in the standard format for all files sections up to and including section 9999. The alphanumeric count is only employed from section 10,000 onwards.

If you have or are likely to have high capacity tapes then you must decide which optional repairs are appropriate for your system.

For further information please see SKEs 77441 and 95662 together with the 'Special Instructions' and 'Effect of Repair' sections of the above repairs.

Should further assistance be necessary then please contact your local Fujitsu Services support centre for advice.