Restoring data

When restoring data that was created in a Pick-compatible environment, or on any other D3 or Advanced Pick platform, special options might be required to restore that data to D3.

Tape labels

Some systems create tapes with a label consisting of 80 bytes, some with 512 bytes, and some with no labels at all. Label size and format might be device and D3 version dependent.

Labels contain a variable number of characters up to 47, depending on the length of the Timedate stamp and Platform ID.

In D3 version 7.1.0, the label size for 8mm tape was changed from 512 to 80 bytes. Tapes created on earlier releases of D3 7.2.1 or AP can be read using this release by setting the label to 512 bytes.

To read D3 tapes on other platforms using an earlier release of D3 or Advanced Pick, the label size must be adjusted to 80 bytes.

Where n is the device number:

To change the label size to 512 bytes, enter the following:
```
chg-device n label=512
```
To change the label size to 80 bytes, enter the following:
```
chg-device n label=80
```

Tape format

D3 uses two different device drivers when writing to tape:

A fixed-block device driver for writing to quarter-inch media
A variable length driver for other tape devices (8mm, 4mm, a DLT and so on)

For example: A 4mm tape might have been written using a 1/4" device driver. The system on which D3 is loaded must be capable of using alternate device drivers. The pick0 configuration file, from which you are migrating, must be modified in the tape lines to show usage of alternate drivers.

Blocking factors

If a tape is not readable, consider whether the source and target systems use the same UNIX blocking factors. If the tapes were created with a fixed block size, or variable-length block size, they must be read in the same way.

For 4mm and 8mm tape, it is highly recommended that the default block size always be set to variable block size mode

Warning: Using the wrong tapes or blocking factors can destroy your file system.

Restore options

Tape compatibility restore options are:

Non-D3 tapes:
Use the (F option.
AP/Native and AP/DOS:
Use (F1000 and refer to Frame Size in this section. For example:
```
account-restore (F1000
```
R83:
Use (F500 and refer to Frame Size in this section.
R91, mvBase, and mvEnterprise:
Use the (Q option on restores. For example:
```
restore-accounts (FQ
```
Microdata/McDonnell Douglas:
Use the (M option on restores. For example:
```
restore-accounts (FM
```
ADDS Mentor:
Use the (E option on restores. For example:
```
restore-accounts (FE
```

Save options

To restore accounts into D3, it might be necessary to generate a tape on the source system using source-specific options:

Mentor O/E style file-saves:
Use the (E) option to support restoring accounts.
mvEnterprise, mvPro, SEQUOIA Pro:
Use the (B) option to support restoring accounts.
mvPro and SEQUOIA Pro:
Use the (B) option when setting the tape device.
SEQUOIA Pick:
Release 2.0 and above: Use the (B) option to generate save tapes.

Release 1.8: No options are necessary.
For other Pick compatible systems:
The file-save tapes might need to be created as R83 compatible. Typically, using the (C) option.

End-of-file marks

There might be a difference between D3 and the source system with the End-of-File and End-of-Data marks on the tapes.

If a restore is in progress and a prompt appears for another reel, but there are no more reels, use the letter q to quit the restore.
If a restore terminates when skipping accounts that already exist on the system (for example, if a dm account is on the tape), load the next reel and re-enter the restore-accounts command.
If a restore does not restore across tapes, use the (C) option. This is typically only required when upgrading from an older Pick operating system.

Frame size

D3 uses a frame size of 4 KB for all UNIX platforms. If the frame size is not the same as that of the source system, restore options should include the frame size of the source system.

Examples:

The following command restores from a tape where the originating system had a frame size of 2 KB, for example a D3 7.3.x system.

restore-accounts (F2000

The following command restores from a tape where the originating system had a frame size of 1024. If this is not done, then potentially twice as much disk space (or more) will be allocated as is necessary.

restore-accounts (F1000

For mvEnterprise, mvPro, SEQUOIA Pro, and SEQUOIA Pick tapes, use:

restore-accounts (FQ4000