Sage II - Disk Bootstrap

sAcE
rI
sERvrcE
MANUAL
[1.0]
POWER-UP
ROUTINE
DISK
BOOTSTRAP
VII.O3
DISK
BOOTSTRAP
:
Next,
the
bootstrap
swltches
are
to
boot
to:
read
to
determlne
what
devlce/program
sn6
sw5
dwn
dwn
dwn
up
up
dwn
up
up
BOOT
DEVICE
boot
to
DEBUGGER
boot
to Floppy
drive
0.
reserved,
defaults
to
DEBUGGER
reserved,
defaults
to
DEBUGGER
If the
rear
panel
swltches
are
set
to boot
from
a
floppy
the
screen
wlll
dt
splay:
rrBootLng
from
Floppy"
Then
the first
lK
of
the
BOOT
dlskette
(flrst
2
sectors
of
5lZ byres
each)
are
read
lnto
memory
at
locatlon
400
hex.
The flrst
4 bytes
of
thls
area
should
be the
ASCII
string
'B0OT'
=
42 4F
4F
54
hex.
If thts
lnformatlon
ls
not
there
then
an error
message is
dlsplayed:
"Not
Boor
dlsk"
If a tlmeout
occurs
while
trying
to
access
the
diskette,
-he
program
assumes
there
is
no
dlskette
there
and
outputs:
"Put
ln
B00T
disk and
press
a k"y"
Typing
a
rrQrr
wtll
dlsplay
tfBoot
aborted
on
drlve
Ott
and
control
w111
go
to
the
DEBUGCER.
re-try
to
boot from
the
Floppy.
Typlng
any
other
key
w111
cause
a
If
the
aystem
appears
to
try
to
boot,
but
dies before
dtsplaylng
the
pronpt
1lne for
the
operating
system,
the
probleur
may
1le
ln
the
lnterrupt
systen.
A11
I/O up
to this
polnt
was
done
uslng
the
polled
drlvers
ln
the
monitor
ROM.
Once the
system ls
read from
the floppy,
the
lnterrupt
drlven
I/O
routlnes
ln
SYSTEM.BIOS
are
used.
The
system
flles
can be
verlfted
lf
another
working
SAGE
II
ls
present.
The floppy
drlve
could
also
be
readlng
the files
tncorrectly.
t2