Specifications
3.7
USING
FLOPPY
DRIVES
DOS compatible floppy disk functions are provided within the ROM-BIOS. Diskettes may be
copied,
formatted, verified, etc. using the standard DOS commands. This includes all of the
DOS mini (5-1/4") and micro (3-1/2") floppy formats --
1601(,
1801(,3201(,3601(,
7201(,
1.2M,
and l.44M -- provided the appropriate version
of
DOS
is
used (see Chapter 2).
In
addition,
dual capacity use of high density floppy drives is supported, which means· that 360K floppies
can be read in a 1.2M 5-1/4" drive, and
720K floppies can be read in a l.44M 3-1/2" drive.
The
Little
Board/PC
has a number
of
configuration jumpers which must
be
set according to
the number and
type
of floppy drives connected to the system. Be sure to set the jumpers
as
described in Chapter
2.
One
handy feature of DOS is its built-in support for single-drive systems.
If
you jumper the
board
for only one floppy drive,
the
operating system will automatically assign drive letters
"A"
and
"B"
to the single floppy drive. With this configuration, you can copy mes between two
diskettes
on
one drive, as though your system has
two
drives; DOS
will
prompt you
to
change
diskettes when needed.
3.8
USING
SCSI
HARD
DISK
DRIVES
One
unique
feature
of
the
Little
Board/PC
is
that
its
ROM-BIOS
contains
PC/XT
compatible
hard
disk support functions which
map
to
the board's Small
Computer
System
Interface, rather than to a standard
PC
bus hard disk controller. This has the advantage of
offering the added flexibility of
SCSI device support, with its benefits
of
interchangeability
of
peripherals, flexibility of configuration, and ease of system upgrading and support.
A hard disk device accessed via the board's
SCSI interface is available to DOS through stand-
ard ROM-BIOS functions (INT 13), supplied by the Ampro SCSI/BIOS contained within the
board's
ROM-BIOS. The ROM-BIOS hard disk support allows direct system booting from a
SCSI Common Command Set
direct
access
device.
In
addition to hard disks, other types of
SCSI
direct
access
devices
can be used interchangeably to provide a fully compatible hard disk
function. These include bubble memory drives, RAM disks, optical disks, and tape drives.
Virtually all
DOS
applications
run
normally in this SCSI-based
hard
disk environment,
be-
cause programs nearly always use either DOS
or
ROM-BIOS functions for disk drive access.
It
is extremely rare for DOS environment software to attempt
to
access
hard
disk controller
hardware
directly.
If
a program does require disk controller
hardware
access, it
will
need to
be modified
to
use
the
board's SCSI hardware
or
SCSI/BIOS
functions.
In
this case, low
level
SCSI functions available within the board's ROM-BIOS can be used to simplify the task.
In
most cases, a SCSI hard disk drive can be used without the need for custom programming.
The
board's
ROM-BIOS
and
SCSI support software allow the use
of
one
hard
disk drive
under
PC-DOS, MS-DOS, DR-DOS.
3-8