by Harold D. Portnoy
When an AppleWorks word processor or data base file goes bad is not the time to worry about how you are going to repair the damage.
CHANGE-A-FILE (CHGFIL.BXY) is a batch file utility that reads AppleWorks Word Processor (AWP) and text (TXT) files; converts AWP files to TXT files, TXT files to AWP files, and AWP 3.0 files to AWP 2.x files; and rapidly repairs damaged AWP and ADB (data base) files.
While CHANGE-A-FILE can readily restore damaged AppleWorks word processor (AWP) and data base (ADB) files, it cannot restore a file on a disk with a damaged directory. RESURRECTION can restore these files …. most often rapidly, but occasionally with a little work. The disk blocks containing the file that cannot be accessed are still on the disk. The problem is where are the blocks and how can they be placed in an accessible file. RESURRECTION answers these two questions. RESURRECTION is not a substit ute for Change-A- File (see note below). RESURRECTION - -
Insert the damaged disk (source) into a disk drive and then enter the slot and disk number or accept the default values. The complete file name, including the prefix, of the file to be created (destination) from the damaged file is then entered. The destination file cannot be on the disk in the source slot/drive. This prevents the new file from being on a damaged disk. Next the filetype is selected (TXT, AWP, or ADB). The destination file does not have to be completed in one session. To append to a partially completed file, enter the destination file name. At 'File already exists. Replace? (N/Y)', enter 'N'. At 'Append ? (N/Y)', enter 'Y'. New blocks will then be added to the end of the previous file.
The function screen is divided into an upper and lower half. The file name
is printed in the left upper corner and the total blocks on the source disk in the right upper corner. The number of blocks on the disk is initially determined from the volume directory on block 2. If block 2 is damaged, then an attempt is made to determine volume size by two other methods. If all methods fail, then a 'VOLUME BLOCKS $' window will open. Enter the volume size in blocks. This should be rarely necessary. The follow ing can be used to determine the number of blocks. A 5.25 inch disk has $118 blocks (140 blocks); a 3.5 inch disk, $640 (1600 blocks); and hard discs, $800 * size in megabytes. The functions are printed on the bottom line of the screen. The following can be selected: Arrows, Quit, Read, Write, Dump, Scan.
Read: Blocks from the damaged disks are accessed either by the up and down arrows, which select the blocks sequentially, or by entering 'R'. A window appears with 'Read Block $'. Enter the desired block number. The block is displayed in the lower half of the screen. The block number is displayed in the left margin at 'Read Block'. For ease of review, only the characters in the range of $20 - $7F (the text characters) are printed to the screen. All other characters are replaced with a period.
Write: Enter 'W' to write the block to the new file. The block is displayed on the upper half of the screen. Only a previously read block can be written to file. The block number is displayed in the left margin at 'Write Block'. The next block in the file can be accessed by the arrows or 'R' and the process repeated until all the blocks in the old file are transferred to the destination file. Once a block in the source file is found, succeeding blocks are frequently found in sequential order and easily accessed by the up arrow.
Dump: Any block that has been read can be dumped to the printer by entering 'D'. The easiest way to reconstruct a file is to first dump all the blocks, which are identified with a block number, to a printer. Determine the order of the blocks. Reenter the program and write the blocks to the destination file in the proper order. The printer output is set to slot 1. If you use a different slot, then change the low nibble of byte $03 (C1) to the slot number. This is most easily accomplished using a block editing utility such as ProSel Block Warden. Alternately the following patch will suffice after setting the prefix to the directory containing RESURRECTION.
POKE 768,19n (where n = slot number + 2)
Scan: Scan allows bad blocks to be easily identified. Selecting 'S' brings up the 'SCAN BLOCK $' window. Enter the block number from which the scan should start. The bad block numbers will then be printed in hex. The scan can be interrupted by pressing any key. The block numbers can also be sent to a printer.
Auto-Restore: There are two Auto-Restore functions: by file name and by index block. Auto-Restore by file name is the best method to restore a file. It requires, however, that a parent directory be intact. Auto-Restore by index block only requires that the index block of the file be intact. It is less efficient than restoring by file name and should be used only after Auto- Restore by file name has failed. It is much more efficient than reconstructing a file using the Read/Write functions. Entering 'A' brings up a menu for selecting either Auto-Restore by file name or by index block.
Auto-Restore by file will restore a file as long as the parent directory or subdirectory and the index block(s) of the file are intact. If the volume directory is damaged or any of the other directories up to, but not including, the parent subdirectory, the file can still be recovered. A common cause for failure to access a file is damage to the volume directory in block 2. If the directory file entry of the file is not in block 2, the file can be recovered. On selecting by file name, the 'Find File' window is opened. Enter the file name only. Do NOT enter any prefix. The file type must be the same as previously selected. Auto-Restore will search the damaged disk for the file.
Pressing any key will abort the search. If the file is found, identifying attributes are displayed in a window. The attributes are parent directory or subdirectory, file type, size in blocks, and modification date and time. If this is the correct file enter 'Y' at 'Accept (N/Y)'. If not, you will be given the option of continuing the search or aborting.
When the file is accepted, Auto-Restore automatically reconstructs the
damaged file under the destination file name. DO NOT INTERRUPT the reconstruction. When complete the program returns to the input menu.
Auto-Restore by index block requires that there be at least two blocks in the file and cannot directly handle files in excess of 256 blocks. It is ideal for sapling files, that is, files of 2 - 256 blocks. Most files fall into this category. It cannot detect seedling files (1 block). Tree files ( > 256 blocks) must be reconstructed from file segments of 256 blocks. The algorithm used to detect an index block may not detect all index blocks and may recognize a non- index block as an index block (pseudo- index block). The former is more important in that a desired file cannot be detected.
Selecting Auto-Restore by index block presents a new function screen:
Select Arrows (up and down), Accept and Next index block; and an 'Index Block $' window. Enter '0' in the window, when searching for a file for the first time. If you have an idea of approximately where the file is on the disk, then enter a block number that is known to be before the index block of the file. Select 'N'. The disk will be searched for an index block. When found, the first two blocks of the file will be displayed on the screen. If you need more information in order to decide if you have the correct file then select the up arrow and two more blocks will be presented until the file ends. Selecting the down arrow, backs up two blocks.
When you are satisfied that the correct file has been found, select 'A'
and the file will be reconstructed. In the search, errors such as 'Bad Block' and 'Block Range Error' may be encountered. The former indicates a bad block has been encountered. The latter indicates that the algorithm found a pseudo- index block and a file block number was tried that exceeded the volume size. Continue by selecting 'N' for the next index block.
With a little time and effort, tree files can be first reconstructed into
multiple files of 256 blocks. AppleWorks can then be used to append one file to the next in order to reconstruct the original tree file. Not the best, but better than block by block.
Quit: Enter 'Q' to complete the destination file.
ESC: Entering ESC at any point in the program resets to the initial screen. At the initial 'Slot' request, ESC quits the program. The destination file is not saved.
NOTE The text files can be read with any appropriate utility such as 'View' in Change-A-File. AWP and ADB files must first be processed by Change-A- File's 'AWP File Doctor' or 'Restore ADB' in order to be accessed by AppleWorks.
Icons CF.RES.ICONS contains Change-A-File and Resurrection icons. The Change-A-File icon is courtesy of Karl Bunker. To use these icons in the Finder, place CF.RES.ICONS in the ICONS subdirectory of the boot volume (BOOT.VOLUME/ICONS/CF.RES.ICONS) and reboot. The two programs must have file names of CHANGE.FILE and RESURRECTION.
Auto-Restore is not accessible unless you have the CHANGE-A-FILE password. If RESURRECTION is placed in the same directory as CF.SYSTEM, the Auto-Restore function will be unlocked on entering the password and then quitting CHANGE.FILE.
Transfer the CHANGE.FILE and RESURRECTION files to the volume directory of
a disk under ProDOS (P8). Rename CHANGE.FILE to CF.SYSTEM. Be sure this file is the first .SYSTEM file in the directory (e.g. ahead of BASIC.SYSTEM). Boot the disk. (You must boot directly into CF.SYSTEM.) The password screen will be presented. Enter the password. When the menu is presented, select Quit. The CHANGE.FILE will be rewritten to the disk without the screen. The Auto-Restore function of RESURRECTION will be activated. Rename CF.SYSTEM to CHANGE.FILE or any other name of your choice. Whether you have the password or not, the password screen will be removed. If you enter the password, all the utilities will be able to be used in both programs. If not, only the 'free' utilities will be able to be used.
The CHANGE-A-FILE password can be obtained for $10.00 from:
Change.File c/o Harold D. Portnoy 1431 Woodward Bloomfield Hills, MI 48013
All rights reserved.
AppleWorks, copyright Claris Corporation ProSel, copyright Glen Bredon
Suggestions, bugs and other trivia to:
Harold D. Portnoy
Compuserve [75156,2436] GEnie [H.PORTNOY]
1.0- First attempt. 1.1- Improved layout and docs. Adds scan. 1.2- Adds Auto-Restore. 1.3- Improved Auto-Restore. Also removes bug. 1.4- A few bug fixes and minor improvements. 1.5- Improved determination of volume size and a bug fix. 1.6- Adds Auto-Restore by Index Block. 1.7- Improved algorithm for Auto-Restore