<s>
IDEDOS	B-Operating_System
is	O
a	O
ROM-based	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
written	O
in	O
6502/65816	O
assembly	B-Language
language	I-Language
for	O
the	O
Commodore	O
64	O
,	O
128	B-Device
and	O
SuperCPU	O
.	O
</s>
<s>
Its	O
main	O
purpose	O
is	O
to	O
control	O
ATA(PI )	O
devices	O
connected	O
to	O
an	O
IDE64	B-Device
cartridge	O
and	O
present	O
them	O
like	O
normal	O
Commodore	O
drives	O
.	O
</s>
<s>
Additionally	O
it	O
supports	O
networked	O
drives	O
(	O
PCLink	O
)	O
and	O
has	O
a	O
built-in	O
machine	B-General_Concept
code	I-General_Concept
monitor	I-General_Concept
and	O
file	B-Application
manager	I-Application
.	O
</s>
<s>
The	O
C64	O
KERNAL	B-Operating_System
uses	O
a	O
vector	O
table	O
at	O
page	O
3	O
to	O
allow	O
redirection	O
of	O
common	O
kernal	B-Operating_System
file	O
handling	O
and	O
basic	O
functions	O
.	O
</s>
<s>
This	O
feature	O
is	O
used	O
by	O
IDEDOS	B-Operating_System
to	O
hook	O
into	O
the	O
C64	O
kernal	B-Operating_System
.	O
</s>
<s>
Additional	O
RAM	B-Architecture
for	O
buffers	O
and	O
internal	O
data	O
are	O
also	O
mapped	O
in	O
from	O
either	O
the	O
IDE64	B-Device
cartridge	O
(	O
28KiB	O
)	O
or	O
the	O
additional	O
RAM	B-Architecture
of	O
the	O
SuperCPU	O
is	O
used	O
.	O
</s>
<s>
The	O
standard	O
kernal	B-Operating_System
memory	O
locations	O
at	O
page	O
zero	O
and	O
page	O
two	O
are	O
handled	O
in	O
a	O
kernal-compatible	O
way	O
;	O
temporarily	O
used	O
memory	O
is	O
restored	O
after	O
the	O
routines	O
are	O
finished	O
.	O
</s>
<s>
Beyond	O
the	O
kernal	B-Operating_System
table	O
IDEDOS	B-Operating_System
has	O
two	O
new	O
calls	O
for	O
bulk	O
data	O
handling	O
(	O
read/write	O
)	O
which	O
allows	O
much	O
faster	O
data	O
transfer	O
rates	O
than	O
the	O
character-based	O
I/O	O
.	O
</s>
<s>
Due	O
to	O
complexity	O
and	O
memory	O
requirements	O
,	O
the	O
filesystem	O
creation	O
and	O
consistency	O
check	O
is	O
not	O
part	O
of	O
the	O
operating	O
system	O
,	O
unlike	O
CBM	B-Device
DOS	I-Device
or	O
CMD	O
DOS	O
.	O
</s>
<s>
Additional	O
filesystems	O
like	O
ISO	B-Application
9660	I-Application
or	O
FAT	B-Application
are	O
abstracted	O
internally	O
and	O
mostly	O
use	O
the	O
same	O
routines	O
for	O
handling	O
,	O
thereby	O
little	O
difference	O
is	O
noticeable	O
to	O
user	O
programs	O
,	O
except	O
if	O
some	O
features	O
are	O
not	O
fully	O
implemented	O
.	O
</s>
<s>
The	O
device	O
numbers	O
for	O
IDEDOS	B-Operating_System
devices	O
are	O
configurable	O
and	O
is	O
normally	O
in	O
the	O
range	O
of	O
10	O
–	O
14	O
.	O
</s>
<s>
Over	O
the	O
years	O
many	O
programs	O
assumed	O
that	O
there	O
is	O
only	O
device	O
8	O
and	O
do	O
not	O
allow	O
selecting	O
anything	O
else	O
;	O
this	O
can	O
be	O
worked	O
around	O
by	O
temporary	O
changing	O
the	O
used	O
IDEDOS	B-Operating_System
device	O
number	O
to	O
8	O
.	O
</s>
<s>
For	O
standard	O
devices	O
,	O
the	O
original	O
kernal	B-Operating_System
routines	O
are	O
used	O
,	O
while	O
IDEDOS	B-Operating_System
devices	O
use	O
custom	O
routines	O
which	O
closely	O
imitate	O
the	O
results	O
and	O
behavior	O
of	O
kernal	B-Operating_System
calls	O
for	O
floppy	O
devices	O
.	O
</s>
<s>
Kernal	B-Operating_System
calls	O
not	O
going	O
through	O
the	O
vector	O
table	O
(	O
most	O
notably	O
IEC	O
bus-specific	O
calls	O
)	O
present	O
an	O
incompatibility	O
with	O
those	O
programs	O
using	O
them	O
.	O
</s>
<s>
Special	O
features	O
(	O
like	O
CD-ROM	O
audio	O
handling	O
)	O
are	O
implemented	O
by	O
new	O
channel	O
15	O
commands	O
,	O
while	O
features	O
not	O
found	O
on	O
floppy	O
drives	O
follow	O
the	O
CMD	O
style	O
commands	O
to	O
allow	O
programs	O
to	O
easily	O
support	O
a	O
wider	O
range	O
of	O
devices	O
.	O
</s>
<s>
Unlike	O
intelligent	O
external	O
devices	O
which	O
have	O
a	O
separate	O
processor	O
(	O
like	O
1541	B-Device
with	O
CBMDOS	O
)	O
,	O
IDEDOS	B-Operating_System
runs	O
on	O
the	O
host	O
computer	O
,	O
thereby	O
all	O
disk	O
routines	O
block	O
until	O
finished	O
.	O
</s>
<s>
Interrupts	O
are	O
generally	O
allowed	O
while	O
IDEDOS	B-Operating_System
is	O
running	O
(	O
they	O
are	O
disabled	O
on	O
rare	O
time-critical	O
operations	O
)	O
,	O
however	O
the	O
system	O
was	O
written	O
to	O
be	O
non-reentrant	O
,	O
just	O
like	O
the	O
original	O
kernal	B-Operating_System
.	O
</s>
<s>
In	O
1996	O
IDEDOS	B-Operating_System
was	O
born	O
,	O
as	O
there	O
was	O
a	O
need	O
for	O
a	O
system	O
to	O
run	O
the	O
IDE64	B-Device
1.1	O
card	O
.	O
</s>
<s>
It	O
was	O
created	O
by	O
Josef	O
Souček	O
(	O
main	O
code	O
)	O
and	O
Tomáš	O
Přibyl	O
(	O
File	B-Application
manager	I-Application
,	O
Final	O
cartridge	O
monitor	O
adaptation	O
)	O
.	O
</s>
<s>
Additional	O
code	O
came	O
by	O
Jan	O
Vorlíček	O
(	O
BASIC	B-Language
extension	I-Language
)	O
,	O
Jan	O
Hlaváček	O
(	O
Duart	O
PCLink	O
)	O
.	O
</s>
<s>
In	O
2009	O
the	O
64KiB	O
limit	O
for	O
the	O
system	O
started	O
to	O
get	O
tight	O
,	O
and	O
the	O
IDEDOS	B-Operating_System
0.91	O
beta	O
was	O
started	O
to	O
refactor	O
the	O
code	O
to	O
gain	O
more	O
space	O
and	O
internal	O
flexibility	O
.	O
</s>
<s>
This	O
was	O
the	O
last	O
version	O
of	O
the	O
old	O
IDEDOS	B-Operating_System
series	O
.	O
</s>
<s>
Built	O
in	O
fast	B-Device
loader	I-Device
supported	O
devices	O
:	O
</s>
<s>
Fast	O
load	O
can	O
be	O
switched	O
off	O
in	O
setup	O
in	O
case	O
of	O
incompatibility	O
(	O
non-1541	O
as	O
device	O
8	O
)	O
.	O
</s>
<s>
PAL/NTSC	O
compatible	O
timing	O
.	O
</s>
<s>
Includes	O
clock	O
with	O
calendar	O
,	O
ability	O
to	O
set	O
drive	O
numbers	O
,	O
screen	O
colours	O
,	O
auto	O
boot	O
,	O
floppy	O
fast	B-Device
loader	I-Device
,	O
basic	O
clock	O
(	O
TI$	O
)	O
,	O
power	O
management	O
,	O
write	O
retry	O
,	O
read-ahead	O
and	O
write	O
cache	O
drive	O
settings	O
,	O
CDROM	O
slow	O
down	O
option	O
.	O
</s>
<s>
The	O
BASIC	B-Language
extension	I-Language
includes	O
disk	O
handling	O
commands	O
(	O
limited	O
to	O
IDEDOS	B-Operating_System
devices	O
)	O
,	O
and	O
adds	O
some	O
new	O
error	O
messages	O
.	O
</s>
<s>
The	O
monitor	O
is	O
almost	O
exactly	O
the	O
Final	O
cartridge	O
monitor	O
in	O
IDEDOS	B-Operating_System
0.89	O
.	O
</s>
<s>
Only	O
standard	O
6502	B-General_Concept
opcodes	O
are	O
available	O
.	O
</s>
<s>
The	O
battery	O
on	O
the	O
IDE64	B-Device
cartridge	O
can	O
be	O
replaced	O
with	O
a	O
supercap	O
now	O
.	O
</s>
<s>
PAL/NTSC	O
compatible	O
timing	O
.	O
</s>
<s>
Fast	O
saver	O
only	O
in	O
the	O
file	B-Application
manager	I-Application
.	O
</s>
<s>
Mostly	O
the	O
well	O
known	O
standard	O
DOS	B-Operating_System
wedge	I-Operating_System
commands	O
.	O
</s>
<s>
The	O
BASIC	B-Language
extension	I-Language
adds	O
disk	O
handling	O
commands	O
,	O
which	O
can	O
be	O
used	O
with	O
any	O
device	O
because	O
they	O
use	O
CMD	O
style	O
commands	O
.	O
</s>
<s>
The	O
file	B-Application
managers	I-Application
inspiration	O
comes	O
from	O
0.89	O
,	O
though	O
it	O
was	O
rewritten	O
from	O
scratch	O
.	O
</s>
<s>
The	O
goal	O
was	O
to	O
have	O
a	O
file	B-Application
manager	I-Application
which	O
not	O
only	O
supports	O
IDEDOS	B-Operating_System
devices	O
,	O
but	O
also	O
works	O
well	O
with	O
CMD	O
and	O
other	O
drives	O
.	O
</s>
<s>
The	O
goal	O
was	O
to	O
have	O
freezer	O
style	O
(	O
all	O
registers	O
including	O
I/O	O
editable	O
)	O
and	O
fast	O
machine	B-General_Concept
code	I-General_Concept
monitor	I-General_Concept
which	O
supports	O
illegal	O
6502	B-General_Concept
and	O
SuperCPU	O
emulation	O
mode	O
opcodes	O
.	O
</s>
