STERNLIGHT%USC-ECL%sri-nic@sri-unix.UUCP (11/29/83)
From: David Sternlight <STERNLIGHT%USC-ECL@sri-nic> There is a bug in sd-77 which has been around for a while. When SD goes to look at the S2 byte of the file control block to see if there are more extents than 3, it looks at the whole byte. This is inconsistent with CP/M practice, which uses the lower 4 bits only of this byte. (Never mind what David Cortesi says in his book; he is mistaken.) Thus an ani 0fh needs to be inserted in the code to mask out the relevant bits. Otherwise, programs such as qbax, which use the higher bits for such things as archive flags will (if they set a file as backed-up) cause sd to report the file size as 256k too large. The place for the ani 0fh is just following the (second) LDAX D after TMOVE:, which loads the s2 byte. --david--