Each item or record requires some number of bytes for system overhead. This is called the item header. The item header consists of eight bytes:
|
four |
bytes (unused) |
|
two |
bytes for the item size pointer points to the (trailing) segment mark, not the beginning of the next item |
|
one |
byte for item flags |
|
0 |
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1 |
item deleted since last full save |
if D-pointer, file stolen from another account |
if D-pointer, file cleared since last full save |
if D-pointer, file renamed since last full save, else new item-locked |
item was updated since last full save |
a D-pointer |
a binary item |
a pointer item |
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|
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
one |
byte for the number of file-saves performed |
At the time a full save is completed, the system clears bits 2, 4, 5, and 7 from the item flags in all items. The message clearing dirty bits, seen during the file-save process, indicates this procedure is taking place. It is desirable not to perform this cleanup until after the full save is known to be valid. This byte is used to identify whether the item was updated before or after the full save.
See Also