copyright David T. Craig - May 1993
This document describes how to deserialize the Lisa computer's Office System 1 disk. This disk is used by Lisa computer owners to install Apple's Office System software, release 3 which is also called "Lisa 7/7". Deserializing a disk makes the disk usable on Lisas other than the original Lisa which was first used to install the Office System software.
I used the Macintosh application FEdit 3.0 to deserialize the Office System 1 disk.
WARNING
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You should make a copy of the Office System 1 disk before attempting this deserialization since this document describes a technique that can easily damage the Office System disk beyond all hope.
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The deserialization technique basically consists of changing several bytes on the Office System 1 disk so that the disk appears to the Lisa as a "virgin master". A virgin master disk can be installed on any Lisa. But once installed a virgin master becomes a "serialized master" which can only be used on the Lisa which installed it first. A serialized master has the Lisa's unique serial number written to it (see the last page for Lisa serial number information).
Run FEdit on your Macintosh and perform the following steps:
0) Press the mouse button in FEdit's introduction window to remove the window from the screen.
1) Insert the Office System 1 disk into a Macintosh disk drive. FEdit displays a dialog stating that the disk is not a Macintosh disk and asks if the disk should be mounted or ejected. Select the MOUNT button.
2) Select OPEN VOLUME from the FILE menu. Press the dialog's DRIVE button until the "internal drive" message appears. Select the dialog's OPEN button. You should see a window titled "internal drive" and showing a bunch of stuff in the window.
3) Select DISPLAY SECTOR IN HEX from the DISPLAY menu. The "internal drive" window should now show an orderly arrangement of numbers and letters A to Z on the left (I call this the "hex area" since it contains hexadecimal numbers) with characters on the right (called the "character area"). See the attached screen image at the end of this document for a sample of this window. Note that the window's top contains several lines, one of which reads "Sect: 0". This means sector 0.
4) Select the window's horizontal scrollbar "page right" arrow until the SECTOR information at the top of the window changes to "1C".
5) Select HEX MODIFY from the EDIT menu. "*** Hex modify active ***" should appear in the menubar.
6) Use the mouse to click on byte at location CC in the window. This byte will be located in the row labeled C0 and four bytes from the right of the window's hex area edge. In the sample window figure this byte contains the value 00, the three bytes to its right contain 011517.
7) Change the bytes at locations CC to CF to be all zeros. Just type the zeros using the Macintosh keyboard.
Verify very carefully that you have only changed the four bytes. If you change any other bytes by mistake quit FEdit and start over.
9) Select WRITE SECTOR in the EDIT menu. Answer in the affirmative to FEdit's question about writing the sector back to the disk.
10) Quit FEdit using the QUIT command in the FILE menu.
Now you should have an Office System 1 disk that can be used to install the Lisa Office System on your Lisa.
NOTE : The numbers at locations CC-CF contain the serial number of the Lisa which was used first to install the Office System software. My Lisa has serial number 70,935 which is the same as the hex number $00011517. In general, the serial number at locations CC-CF should be below 100,000 (around hex $00012000) since Apple never produced more than 100,000 Lisa computers.
NOTE : From the Lisa Office System you can determine your Lisa's serial number using the "Attributes" command in the File menu after selecting the Lisa's Preferences tool.
NOTE : See my earlier paper titled "Apple Lisa 7/7 Tool Serialization" (1988) for details about how to deserialize specific Lisa tools (eg LisaCalc).
Diagram of FEdit window showing Office System Disk 1 sector $1C BEFORE deserialization
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Lisa Disk Sector Page Label Information
David T. Craig - June 1993
INTRODUCTION
For disk file reliability the Apple Lisa computer maintained special information for each disk sector (sectors are also called "pages" or "blocks" by Apple). This information was called the "page label".
A sector on Lisa disks, either hard disks (e.g. ProFile) or floppies (e.g. 5.25" 860K Twiggy or 3.5" 400K Sony) occupied 512 bytes. Associated with each sector was a group of 24 bytes called the "page label" (also called a "page descriptor" by Apple).
Quoting Apple's Operating System Reference Manual for the Lisa "the page descriptor is stored with the page contents to reduce the destructive impact of an I/O error." From the Lisa Office System software (a.k.a. "Lisa 7/7") whenever the Lisa detected that a disk was in some fashion corrupted the Office System would display a dialog to the user allowing the Lisa user to repair the data on the disk. Internally the Lisa activated a special program called the Lisa Scavenger which performed the actual disk repair.
MACINTOSH NOTE
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The Macintosh computer also used page labels for its disk sectors. But the page labels were called FILE TAGS by the Macintosh development team. See Apple's Inside Macintosh vol. 2, p. 212 for more information. Macintosh file tags occupied only 12 bytes and contained the following fields:
File Number ( 4 bytes )
Flags ( 2 bytes )
Logical Block Number ( 2 bytes )
Last Modification Date ( 4 bytes )
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PAGE LABEL DEFINITION
Apple's Lisa Device Drivers Manual contains a complete definition, via the Pascal language, of the page label structure. This definition appears as follows:
00001 { page label data - stored in disk sector TAG area (24 bytes) }
00002
00003 PageLabel = PACKED RECORD
00004 Version : INTEGER; { 2 - label version number }
00005 DataStat : (DataOK, { 2 - status of page data }
00006 DataMaybe,
00007 DataBad);
00008 Filler : -32..31; { - unused }
00009 Volume : -128..127; { - volume info }
00010 FileId : INTEGER; { 2 - unique file ID }
00011 DataUsed : INTEGER; { 2 - bytes used in page (0-512) }
00012 AbsPage : LONGINT; { 4 - absolute page number }
00013 RelPage : LONGINT; { 4 - relative page number }
00014 FwdLink : LONGINT; { 4 - forward page number link }
00015 BkwdLink : LONGINT; { 4 - backward page number link }
00016 END;
As can be seen from this definition, a page label contains a rather large amount of information (especially when compared to Macintosh file tags). The label begins with a Version number field which I assume was used to differentiate differing label structures (my Lisa disks have version 0). The FileID field contained a unique number which was incremented for each new file that was added to a disk. The DataUsed field contained the amount of data in bytes stored on the page (range: 0 to 512 bytes). The last four fields identified the page's location on the disk in both absolute and relative terms (I assume the Scavenger would try the absolute values first and if these were invalid would try the relative values next, a two-fold repair strategy).
REFERENCES
The following references, all Apple publications or papers, describe Page Labels fairly well. Operating System Reference Manual for the Lisa provides a good overview of Page Labels (called Page Descriptors here to differentiate Page Labels from Lisa File Labels, a 128 byte area that was similar to a Macintosh file's resource fork). Lisa Device Drivers Manual is the best Apple reference since it provides detailed information on the layout of Page Labels, information needed by Lisa disk driver writers.
For a historical look at a system which preceeded the Lisa and supported disk page labels see the Xerox PARC paper Alto: A Personal Computer which discusses the Xerox Alto experimental computer (ca. mid 1970's). Note that the Alto's page labels contained the file id, page number, amount of data used, previous page (absolute), and next page (absolute) fields. Xerox's disk repair program was called the Scavenger, a name which Apple adopted.
Operating System Reference Manual for the Lisa
Apple Computer, 1984, p. 2-3
Lisa Device Drivers Manual
Apple Computer, Jan. 1984, Alpha Draft, section 2.4, DRIVERSDEF source listing
Lisa Hardware Reference Manual
Apple Computer, Jul. 1981, p. 43
The Architecture of the Lisa Personal Computer
Apple Computer, Mar. 1984, p. 4
Alto: A Personal Computer
Xerox PARC (document # CSL-79-11), 1979, p. 25
