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Text File | 1993-07-13 | 15.6 KB | 381 lines

S - P A C K V1.4 S-PACK compresses and packs disks, HD partitions, drawers, and files into as small a volume as possible. It can be used as an archiver, HD Backup, for preparing files for data transmission, and anywhere space on disks needs to be used economically. CALLING S-PACK WorkBench: Click the icon. CLI: Enter "S-PACK", use RUN if you wish. there are no switches or tool types required. CREATING PACKS When S-Pack is called a requester will appear. At the top are four mode buttons, one for each of the available modes: PACK: Click if you are going to make a new Pack. UNPACK: Click if you want to unpack an existing Pack. INDEX: Click to extract the index from a Pack. EXTRACT: Click to extract a single file from a PACK. Below these are four string gadgets. When a mode gadget is switched on any string gadgets not required for that mode will be shaded. FILES: used in Pack and Extract. Pack mode: Either enter the disk, HD partition, drawer or file to be packed, or if more convenient, create a text file which lists the disks, partitions, drawers, and individual files to be included. Partitions/disks must be terminated `:', and each entry must be terminated by pressing the `RETURN' key. An example of a list might be: File: ram:paklist: HD1: df0:apples df1:citrus/oranges Enter the list file name into the requester preceded by `LIST'. e.g LISTram:paklist. Extract mode: enter the file to be extracted . Filename should be written as it appears in the index, however it is not case-sensitive and the wildcard `?' is recognised. Clicking the button just to the left of the gadget will bring up a file requester if you have either Arp.library or ASL.library. PACKFILE: used in all modes. Pack mode: Enter drive, path and name for the pack; the programme will add .PACK or .SE to the name that you enter here, according to whether the Pack is self-unpacking or not. If a floppy drive is called put a disk - normally empty - in the required drive, and QUOTE THE DRIVE (eg df1:) and NOT the disk name. Existing data on the disk will NOT be deleted. Unpack/Index/Extract: Enter the full name and path to the Pack, INCLUDING ANY TERMINATING .PACK or .SE. If unpacking or getting an index from floppies put the LAST disk of the pack in whatever drive is designated. A button is again provided for a file requester. The output may need to be modified to ensure that floppies are referred to by DRIVE and not NAME (for multi-disk packs). TO: used in Unpack, List and Extract Unpack mode: Destination for the unpacked files. Entry can be a disk, HD partition or drawer. If a disk or HD partition you must end with ":". If just a name is entered the program will open a drawer of that name in the Current Directory, and use that. Default destination is a drawer "Output" opened in the current directory. If the destination is a floppy it must be quted by DRIVE name, not disk name. Index mode: Enter filename and path for the extracted index. Default is "RAM:List". Extract mode: Destination for the extracted file. May be a disk, HD partition or drawer. Comments at Unpack mode above apply. Default is "RAM:Extract" A button is provided for a file requester. Again modify the output if necessary to ensure that floppies are referred to by drive, not name. TEMP FILES: can be used in all modes. When packing or unpacking heavy use is made of intermediate files, by default opened in RAM:T. Where ram is limited it can be useful to shuffle these temporary files off to a disk or HD partition. Enter the required drive or partition here, terminating with ":". The programme will add "T" to the drive and if necessary open the new drawer. Below these string gadgets are four more buttons: OK: Accepts the entries and executes. SE: Used only when Packing. Adds a self-unpacking header (6600 bytes) and turns the pack into an executable programme. RECOMP: Used only during Packing. If a file compressed with Power Packer or the standard P-Compress code is encountered it will be re-compressed using S-PACK's more efficient compressor (the same as the SuperC option of P-Compress2). This will reduce the size of the completed pack. On unpacking, such files will be decompressed and not restored to their original state. This may be the normal option if S-Pack is being used as an Archiver. If RECOMP is NOT called the PACK will be a little larger, but on unpacking such files will reappear in their original PP'd or P- Compressed state. This will be the normal option for Backup packs. CANCEL: Clear any entries. To quit, click the close gadget in the top left corner. MULTIDISK operations. Of necessity any programme used for backing up a hard disk must be capable of filling and restoring multiple disks. With S-Pack multi- disk archives can also be created (there is no fundamental difference between a Pack made for HD Backup and one made for an Archive). During Packing a requester will call for a new disk when the current one is full - insert an empty disk, or if you want to end the operation click "Abort". Insertion of a new disk will automatically be recognised. During other operations specific disks (Disk[n], first disk, last disk) may be called. Click "abort" or insert the required disk. During unpacking the programme will call for a new disk if it finds that there is insufficient space on the current disk for the file that is being unpacked. (Calls for a new disk in a hard drive partition have to be ignored and the operation aborted). IF YOU WANT A MULTIDISK PACK TO HAVE AN ICON, YOU SHOULD PUT IT ON THE FIRST DISK OF THE PACK BEFORE YOU START TO CREATE THE PACK ITSELF. (Otherwise there may be no room for it). Don't be in too much of a hurry when changing disks; It is vital to wait for all disk activity to stop. UNPACKING. NON-SELF-UNPACKING PACKS: Call S-pack, If the pack is on floppies put the LAST disk of the pack in a floppy drive, click UNPACK and complete the requester. The programme will first read the index, ask for the first disk, then start unpacking, calling for new disks as necessary. SELF-UNPACKING PACKS A self-unpacking executable will have been produced if the SE button was clicked when creating the pack, and can be identified by the .SE termination. In effect the file on the first disk becomes an executable and calls continuation data from the remaining disks. To use an SE pack: If the pack is on floppies, put the FIRST disk of the pack in any drive. WORKBENCH: Provide the file with a TOOL icon and set two ToolTypes: DEST=<DESTINATION> Use upper-case, no gaps. Enter the drive or drawer into which you want to unpack. Default is ram:X. eg DEST=DF0: or DEST=HD5:apples A drawer "apples" will be opened if necessary. TEMP=<TEMPDRIVE> Use upper-case, no gaps. Enter the drive to be used for temporary files. Default is ram:. Do not omit the `:'. eg TEMP=DF0: Drawer DF0:T will be opened CLI: Call the filename. Include the terminating .SE if present. Two switches are available matching the two tool-types above: -d<DESTINATION> No gap between -d and drive, partition or drawer. -t<TEMPDRIVE> No gap again. Must be a drive or HD partition, not a drawer. eg: df2:HD5BackUp.SE -dHD5:apples -tHD4: This would unpack the file "HD5BackUp.SE" to HD5:apples, using HD4:T for temporary files. Note the colons in HD5 and HD4; they must not be omitted. Defaults are the same, ram:X for destination and ram: for temps. If you type the name followed by `?', eg df2:HDBackUp.SE ?, a Usage string "Usage: xxxx.SE -d<destination> -t<tempdrive>" will be printed to the screen. To otain the index for an SE pack, treat it like a non-SE pack - put the last disk in a drive, call S-Pack, click LIST and complete the requester. Single files cannot be extracted from an .SE pack. FLOPPY DISKS Disks are not re-formatted or re-named automatically, and the necessary number should be cleared and numbered before you start a Pack. DO NOT FORMAT TO THE "FAST FILE SYSTEM" - writing to an FFS disk is a lot slower than to a normal disk! For reasonable writing speed call sys:c/Addbuffers with as high a setting as you can afford; packing will be very slow if the normal default figure of 5 is left unchanged. To ensure that follow-up disks in multi-disk packs can be recognised always use the DRIVE (eg df0:) not the diskNAME. DIALOGUE The output window will show the name of each file as it is packed or unpacked. During compression or decompression of large files the machine may be quiet for some time. To indicate that work is in progress a dot will be printed out at intervals. SPEED. For maximum speed: The `ADDBUFFERS' setting should be as high as possible - desirably at least 100 for any drive or partition used. This will of course benefit all IO, not just S-Pack. Remember that each buffer costs you some 500 bytes of chip memory. Use the Old File System, not FFS. If memory is tight, reboot. This clears fragmentation and improves speed by maximising the memory available. Use RAM for the temporary files. (Use a floppy only as a last resort). MEMORY CONTROL. S-PACK can use a lot of memory. Consider the task of unpacking an .SE pack containing a single file of compressed size 1Mbyte (on two disks), expanding to 2Mbyte decompressed: When the file is called the whole executable - on the first disk - is loaded into memory like any other executable. typically 840 Kbytes Then the two parts are assembled in a temporary file 1000 Kbytes Next provision for decompression is made: filesize(compressed) +130K 1130 Kbytes If (for speed) you are unpacking to ram: add 2000 Kbytes Total 4970 Kbytes This can be reduced to some 1.14 Mbytes: 1. Reduce the size of the executable part (it must have at least the SE header and the start of the first file to be included in the pack - say 8000 bytes) to a minimum by filling all but some 8000 bytes with rubbish before creating the pack, then delete the rubbish. Saves 832 Kbytes. 2 Locate temporary files anywhere there is 1Mbyte to spare - a hard disk partition. A floppy could be used for smaller files but would slow operations considerably. Saves 1000 Kbytes 3. Pack/Unpack directly to the final destination. Saves 2000 Kbytes. If these steps are taken (where relevant) calculate memory usage as: Unpack 130K + largest file (compressed size). Pack 300K + largest file (uncompressed size) but allow as large a safety factor as you can to ensure that problems with fragmented memory are avoided. RECOVERY One of the features of S-PACK is the ability to recover the bulk of data even if one of the disks in the pack develops a fault. Disks prior to the faulty one should unpack correctly. First run the damaged disk through DISKSALV or a similar recovery programme, and try to unpack again. If still faulty, extract the index. This will always be possible if the last disk is OK, and MAY be possible even if there is a fault on this disk. Using the index and the EXTRACT option of S-PACK extract files from disks following the faulty disk (non-SE packs only). If the faulty disk can be read at all use the EXTRACT option to get as many files from it as possible (non-SE packs only). Success will depend on the precise nature of the fault. Finally try to load the faulty disk into one of the programmes that allow hex files to be read and written to, and allow the extraction of sections of a file (HEX, BEAV, FILEMASTER). If the pack file on the disk can be loaded, individual files can be extracted using this format data: The format of each file is: Marker: FI (2 bytes) serial number (2 bytes). Bit 15 will be set if the file is not compressed. Uncompressed file: size (4 bytes) data To extract the file just copy the data section to a new file. Compressed file: uncompressed size (4 bytes) compressed size (4 bytes) crc (2 bytes) data To extract the file copy the whole to a new file and change the first 4 bytes (marker + serial number) from FIxx to HILH. You now have a file which can be de-compressed by P-Compress2, or if a text can be read by and saved in clear from the latest version of P-Reader. (V7.1). Alternatively S-PACK the extracted file using the "RECOMP" option and then unpack it. Finally, even if the disk itself is damaged so severely that the PACK file on it cannot be read as a file, it should still be possible to extract sectors using Nic Wison's TRACKDOS and to reconstitute individual files from these. This is not easy. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The compression code used is based on that used in Matthias Meixner's SHRINK archiver, modified to improve speed. A large measure of the credit for S-Pack's performance should be given to Matthias Meixner for this extremely efficient code. S-Pack is Freeware. It may be copied and distributed freely and used without charge for non-commercial purposes. Authority for commercial use should be obtained from the author below. No responsibility can be accepted for any loss occasioned by use of the programme. Chas A. Wyndham, 1265 Canning Mills Road, Roleystone, WA 6111. Australia