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Apple IIc Booting from external drive

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Kevin Stanton

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Jun 4, 1993, 6:53:13 PM6/4/93
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It says ''cannot read disk'' when trying to boot up.
I tried pr#6,2 but it still spun up drive A.

Is there a way to bypass this?

Thanks,
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_/ _/ _/_/_/_/ _/ _/ _/_/_/_/_/ _/ _/
_/ _/ _/ _/ _/ _/ _/_/ _/ Kevin B. Stanton
_/_/ _/_/ _/ _/ _/ _/ _/ _/ Portland State Univ.
_/ _/ _/ _/ _/ _/ _/ _/_/ Dept. of Elect. Eng.
_/ _/ _/_/_/_/ _/ _/_/_/_/_/ _/ _/ kev...@ee.pdx.edu
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Norby

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Jun 4, 1993, 10:13:30 PM6/4/93
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In article <1uojop$k...@donald.ee.pdx.edu> kev...@donald.ee.pdx.edu (Kevin Stanton) writes:
>It says ''cannot read disk'' when trying to boot up.
>I tried pr#6,2 but it still spun up drive A.
>
>Is there a way to bypass this?

It looks like you're trying to boot from an external 5.25 floppy, in which
case I'm afraid there's no getting around it. External 5.25's on a //c
are mapped to S6,D2. Apple //s won't boot from drive 2. (8-bits anyway,
don't know about a gs...)

An external Unidisk 3.5 floppy on the other hand maps to S5,D1. You can
boot from one of those...

--
Internet: drat...@nyx.cs.du.edu
|\ | GEnie: NORBY
| \ | "Leave the night-light on
| \| orby inside the birdhouse in your soul"--TMBG

David Empson

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Jun 5, 1993, 1:14:43 AM6/5/93
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In article <1uojop$k...@donald.ee.pdx.edu> kev...@donald.ee.pdx.edu (Kevin Stanton) writes:
> It says ''cannot read disk'' when trying to boot up.
> I tried pr#6,2 but it still spun up drive A.
>
> Is there a way to bypass this?

Possibly.

First, find out which version of IIc you have by typing PRINT PEEK(64447).

If it says 255, you have the original IIc ROM. Other possible values
are 0, 3 and 4.

The original IIc ROM lets you boot ProDOS from an external 5.25" drive
by typing PR#7. You can't boot DOS 3.3 or Pascal using this method.

All subsequent versions of the IIc (which add UniDisk support) have
this feature removed. If my copy of the IIc hardware reference manual
is to be believed, you can boot from the first external drive by typing
PR#5. I suspect this only applies to a UniDisk 3.5, and not a 5.25"
drive.

Why do you want to boot from the external drive? Is your internal one
faulty or something?
--
David Empson
dem...@swell.actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand

David D Kilzer

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Jun 6, 1993, 12:41:32 PM6/6/93
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>kev...@donald.ee.pdx.edu (Kevin Stanton) writes:

>> It says ''cannot read disk'' when trying to boot up.
>> I tried pr#6,2 but it still spun up drive A.
>> Is there a way to bypass this?

dem...@swell.actrix.gen.nz (David Empson) writes:

>Possibly.

>First, find out which version of IIc you have by typing PRINT PEEK(64447).
>If it says 255, you have the original IIc ROM. Other possible values
>are 0, 3 and 4.

>The original IIc ROM lets you boot ProDOS from an external 5.25" drive
>by typing PR#7. You can't boot DOS 3.3 or Pascal using this method.

>All subsequent versions of the IIc (which add UniDisk support) have
>this feature removed. If my copy of the IIc hardware reference manual
>is to be believed, you can boot from the first external drive by typing
>PR#5. I suspect this only applies to a UniDisk 3.5, and not a 5.25"
>drive.

Yes, PR#5 will boot the first external UniDisk in the //c's drive chain.

I recall typing in a small segment of assembly code (from inCider/A+,
Nibble, or some such magazine) that would boot the external 5.25" drive,
even if you had a //c with newer ROMs. I don't *think* it worked on
anything but a //c, but I can't remember for sure. If you'd like me to
dig it up and post it to the 'net, email me. I'm sure I can find
it...it's only a matter of digging through a few of my BASIC programming
disks. :^)

>Why do you want to boot from the external drive? Is your internal one
>faulty or something?

Yes, that's one of the better reasons to do it. Of course, if you're
REALLY ambitious (and don't mind voiding the warranty on your computer
and disk drive--that is, if there's still one in effect), you can remove
the cover from the //c and from the external disk drive (as long as it's
an Apple External Disk Drive //c), and "swap" the drives. I don't
recall if you could put the //c case back on or not. I seem to recall
that the keyboard needed a small notch in the side of the disk drive
housing for the //c to go back to gether again, but you can certainly
switch them while doing some troubleshooting.

Dave
--
David D. Kilzer \ ST:TNG _Relics_
Computer Engineer 3 / Capt. Montgomery Scott ("Scotty")
ddki...@iastate.edu \ "I may be a captain by rank, but I never
Iowa State University, Ames / wanted to be anything but an engineer."

Robert Church

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Jun 6, 1993, 4:05:43 PM6/6/93
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In article <ddkilzer....@pv343f.vincent.iastate.edu> ddki...@iastate.edu (David D Kilzer) writes:

>Yes, that's one of the better reasons to do it. Of course, if you're
>REALLY ambitious (and don't mind voiding the warranty on your computer
>and disk drive--that is, if there's still one in effect), you can remove

This concern always amused me. Since the //c was discontinued over four
years ago I think most peoples 90 day warranty has pretty much run out.

>the cover from the //c and from the external disk drive (as long as it's
>an Apple External Disk Drive //c), and "swap" the drives. I don't
>recall if you could put the //c case back on or not. I seem to recall
>that the keyboard needed a small notch in the side of the disk drive
>housing for the //c to go back to gether again, but you can certainly
>switch them while doing some troubleshooting.

There's no reason to try and 'cram' the drive into the case. Just plug it into
the internal drives connection.

Bob Church

Stefan Voss

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Jun 7, 1993, 3:13:53 AM6/7/93
to
In article <1uojop$k...@donald.ee.pdx.edu>, kev...@donald.ee.pdx.edu (Kevin Stanton) writes:
|> It says ''cannot read disk'' when trying to boot up.
|> I tried pr#6,2 but it still spun up drive A.
|>
|> Is there a way to bypass this?
|>
I think that you can boot from the //c's external drive into ProDOS (only).
Try this:
1. go to BASIC.
2. put a bootable ProDOS disk in the external drive.
3. Do PR#7.

Hope it works,

Stefan Voss
(vo...@ira.uka.de)

Wulf Hofbauer

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Jun 9, 1993, 3:51:43 AM6/9/93
to
In article <1993Jun5.0...@actrix.gen.nz> dem...@swell.actrix.gen.nz (David Empson) writes:
>
>The original IIc ROM lets you boot ProDOS from an external 5.25" drive
>by typing PR#7. You can't boot DOS 3.3 or Pascal using this method.
>
>All subsequent versions of the IIc (which add UniDisk support) have
>this feature removed. If my copy of the IIc hardware reference manual
>is to be believed, you can boot from the first external drive by typing
>PR#5. I suspect this only applies to a UniDisk 3.5, and not a 5.25"
>drive.

Actually, you can boot from an external 5.25" driver on the //c with ROM
revision 2. The code necessary is in ROM (the ROM listing comments even
tell that you can do it), but due to some omission you can't activate it
by a single command.

You can boot however from the external driver by hacking in a short machine
program. All you have to do is set X to $60, Y to $01, and A to $e0 and
jump do some address... was it $c611? Take a look at the listing...

Oh, yes, it is fun to boot from the external drive as mine has a track zero
sensor and is much more quiet :-)

- Wulf


David D Kilzer

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Jun 12, 1993, 10:49:58 AM6/12/93
to
NOTE: Someone along the line added "comp.sys.apple2.comm" to the
Newsgroups: line. I have removed it since this topic is not relevant to
that group.

>kev...@donald.ee.pdx.edu (Kevin Stanton) writes:

>|> It says ''cannot read disk'' when trying to boot up.
>|> I tried pr#6,2 but it still spun up drive A.
>|>
>|> Is there a way to bypass this?
>|>
>I think that you can boot from the //c's external drive into ProDOS (only).


vo...@i40s16.ira.uka.de (Stefan Voss) writes:

>Try this:
>1. go to BASIC.
>2. put a bootable ProDOS disk in the external drive.
>3. Do PR#7.

>Hope it works,

Only if you have a //c with original ROMs. If you do a PRINT PEEK(64447)
from a BASIC prompt and see the number 255 printed, then you have a
original ROM //c. Here's the stuff from the //c Tech Note #7 about what
PR#7 does, along with some other information. This document and all
other file-type and tech notes are available via anonymous FTP from
ftp.apple.com.

BTW, 64447=$FBBF for those who are hex-deficient. ;^)

-=-=-=-=-=-
Apple II
Technical Notes
_____________________________________________________________________________
Developer Technical Support


Apple IIc
#7: Existing Versions

Revised by: Matt Deatherage November 1988
Written by: Guillermo Ortiz November 1987

This Technical Note describes the main differences between the five different
IIc ROM versions which encompass the original IIc and four revisions.
_____________________________________________________________________________


Original IIc ( $FBBF = $FF )

o Can use the IIc external drive only
o No AppleTalk firmware
o PR#7 boots the second drive
o Mouse firmware maps to slot 4
o Serial firmware does not mask incoming linefeed characters
o Serial firmware does not support XON/XOFF protocol


3.5 ROM IIc ( $FBBF = $00 )

o Can use the IIc external drive and the UniDisk 3.5 drive
o AppleTalk firmware maps to slot 7
o PR#7 returns the message "AppleTalk Off Line"
o Mouse firmware maps to slot 4
o Serial firmware defaults to mask all incoming linefeed characters
o Serial firmware supports XON/XOFF protocol

Original "Memory-Expandable" IIc ( $FBBF = $03 )

o Can use the IIc external drive, the UniDisk 3.5 drive, and the IIc
Memory Expansion Card
o Mouse firmware maps to slot 7
o No AppleTalk firmware
o PR#7 kills the system
o Serial firmware defaults to mask all incoming linefeed characters
o Serial firmware supports XON/XOFF protocol


Revised "Memory-Expandable" IIc ( $FBBF = $04 )

Same as Original Memory-Expandable, plus:
o Keyboard buffering firmware bug fixed
o Firmware returns correct information when the Memory Expansion Card is
not present


Apple IIc Plus ( $FBBF = $05 )

o Can use the external IIc drive, the UniDisk 3.5 drive, the Apple 3.5
drives, but not the original IIc Memory Expansion Card.
o Contains a Memory Expansion Card connector
o 3.5" internal drive replaces 5.25" internal drive
o Mouse maps to slot 7
o PR#7 kills the system
o 4 MHz 65C02 microprocessor
o Accelerator chip and static RAM cache permit operation up to 4 MHz
o Keyboard replaced with Apple Standard Keyboard (minus numeric keypad)
o Internal power supply
o Internal modem connector
o Serial ports refitted with mini-DIN 8 connectors
o Headphone jack has been removed
o Volume control relocated above the keyboard
o 40/80 column switch replaced by keyboard (Sholes/Dvorak) switch


Further Reference
o Apple IIc Technical Reference Manual
o Apple IIc Technical Note #5, Memory Expansion on the Apple IIc
o Apple IIc Technical Note #6, Buffering Blues
o Apple II Miscellaneous Technical Note #2, Apple II Family Identification
Routines 2.1
o Apple II Miscellaneous Technical Note #7, Apple II Family Identification
o Apple II Miscellaneous Technical Note #8, Pascal 1.1 Firmware Protocol
ID Bytes
-=-=-=-=-=-

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