Tandy 1000 Programmer's Reference Guide

ChaDter 5 I Device Drivers
E
R RESERVED U
R
0 Error - If an error occurs, MS-DOS sets the error code
MS-DOS will call BUILD BPB under the following conditions:
0 If “Media Changed” is returned
0 If “Not Sure” is returned and there are no dirty buffers
The BUILD BPB call also gets a pointer to
a one-sector buffer.
What this buffer contains is determined by the NON IBM FOR-
MAT bit in the attribute field. If the bit is zero (device is IBM
format-compatible), then the buffer contains the
first sector of
the first FAT. The FAT ID byte is the first byte of this buffer.
Note: The BPB must be the same,
as far as location of the FAT is
concerned, for all possible media because this
first FAT sector
must be read before the actual BPB is returned. If the NON
IBM FORMAT bit is set, then the pointer points to one sector
of
scratch space (which may be used for anything).
accordingly.
BD
0 ERROR CODE (bit 15 on)
SN
179

Tandy 1000 Specifications

General

Processor	Intel 8088
Processor Speed	4.77 MHz
RAM	128 KB (expandable to 640 KB)
Operating System	MS-DOS 2.11
Manufacturer	Tandy Corporation
Release Year	1984
Storage	Single or double 5.25" floppy disk drive (360 KB), optional hard drive
Sound	Tandy 3-voice sound
Ports	Parallel, Serial
Graphics	CGA (Color Graphics Adapter)
Graphics Modes	320x200, 640x200