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Text File | 1991-04-22 | 37.1 KB | 822 lines

STAC ELECTRONICS 1990 STACKER USER'S MANUAL What is Stacker? ---------------- Stacker provides real-time lossless compression for personal computer hard disks. The Stacker Software Version is for portables and Micro Channel Architecture (MCA) systems. The Stacker coprocessor Version includes an Industry Standard Architecture (ISA) coprocessor board for IBM PC, XT, AT, PS/2 Model 25 & 30, and compatible computers. If you purchased the software version, you can easily upgrade at any time to the coprocessor version if you wish to improve the performance of your Stacker system. Stacker will compress the files on a typical hard disk to about half their original size. The amount of compression you get will bary with the type of files compressed, but overall, about a 2:1 compression ration can be expected. Stacker is designed to work in DOS compatible systems using DOS versions 3.x and 4.x. Because it follows all of the DOS file system conventions, Stacker is compatible with all your utility and application programs. All popular disk recovery utilities, such as UnErase and Norton Disk Doctor, work on Stacker volumes just as they do on uncompressed volumes. Stacker's real-time data compression is performed continuously and without user intervention. This makes Stacker totally transparent. A DOS directory display of a Stacker volume looks just like a directory of an uncompressed volume. Stacker will always show the uncompressed sizes of your files. Once Stacker is installed, it will have no effect on your day-to-day operations. How Stacker Works ----------------- Stacker makes a volume by creating a file on your hard disk which the stacker device driver interprets as a disk drive. This file looks like an additional drive letter to you, to your programs, and to DOS. Any files that are created on or copied to this new drive letter will be compressed automatically. Conversely, as files are read from a Stacker volume, they will automatically be decompressed. The heart of the Stacker system compression system is the device driver called STACKER.SYS. This device driver has two functions: o It acts as a very efficient compression and decompression engine that can compress the average set of files to half their original size. The compression engine performance can be augmented by the addition of the Stacker coprocessor card. o STACKER.SYS is also a file system that presents groups of compressed files as new drive letters. The groups are called Compressed Image Files or CIFs. CIFs reside on your existing hard disk partitions as hidden, system, read-only files. This architecture retains the standard DOS model and provides the greatest possible level of compatibility with DOS, applications, disk utilities and copy protection schemes. The Stacker device driver is a standard DOS block-device driver. An entry in your CONFIG.SYS file loads the Stacker device driver when the system is booted. Parameters in the DEVICE statement tell Stacker where the Stacker coprocessor card is located and where to find the Stacker CIFs. The difference between the Stacker Software Version and Stacker Coprocessor Version is the speed of compression and decompression operations. If a Stacker coprocessor card is installed in your system, the Stacker device driver will turn the jobs of compression and decompression over to the card. The Stacker coprocessor card will enhance the performance of disk write operations, for example, when saving your files. How Stacker Affects Your System ------------------------------- Stacker may be installed in two ways, incremental installation and free space installation. An incremental installation creates a Stacker volume by taking your current hard disk data, compressing it, and copying it to the Stacker. It then verifies that each file was compressed and copied without error, and deletes the uncompressed original. Free space installation creates an empty Stacker volume by letting you allocate a portion of your unused disk space. Both methods are handled by the installation program supplied with Stacker. ******************* DOS 3.0 Through 3.3 ******************* DOS versions 3.0 through 3.3 limit the size of hard disk partitions (drive letters) to 32 Mbytes. Stacker has been designed to respect this barrier to retain compatibility with these versions of DOS. As a result, compressed image files are limited to 16 Mbytes of physical space on the host drive. A 16 Mbyte CIF will result in 32 Mbytes of storage. This means that in some installations you may need to create more than one Stacker volume to take advantage of Stacker compression for all of the hard disk space in your system. Incremental Installation ------------------------ As an example let's assume we're running DOS 3.3 and see how Stacker can be installed on a 20 Mbyte hard disk, drive C. In the installation below, drive C contains 18 Mbytes of data and has about 2Mbytes of unused space. __________ | | | <------ Free (2 Mbytes) |__________| | | | | | | | | | <------ Data (18 Mbytes) | | | | | | |__________| Drive C Before Incremental Installation, DOS 3.x During incremental installation a new Stacker volume, drive D, will be created. Stacker will copy the 18 Mbytes of data stored on drive C to drive D. As each file is copied, it is compressed and verified. Then the original uncompressed version is deleted, making room for additional files to be stored. Two drives, C and D, now exist. Drive D contains 18 Mbytes of data originally stored on drive C, and there are still about 2 Mbytes free. In addition, drive C has about 10 Mbytes of space available for additional files. The resulting drive configuration is shown below. __________ _ _ _ _ _ _ _ _ _ _ _ __________ | | | | CIF | | | <------ Free (10 Mbytes) ------> | |__________| (2 Mbytes) |__________| | | | |\__ | | Free | | \__ | | (9 Mbytes) ------> | \__ | <------ Data |__________| \__ | | (18 Mbytes) | | \__ | | Uncompressed | | \__ | | (1 Mbyte) ------> | \__ | | |__________| Drive C \|__________| Drive D After Incremental Installation, DOS 3.x Copying all of your data from drive C to drive D may have some implications for your batch files and other programs which refer to files and directories on drive C. To eliminate this problem, Stacker comes with a utility called SSWAP which lets your interchange drive letter references. Free Space Installation ----------------------- Free space installation allows you to allocate any or all of the unused space on your hard disk for a Stacker volume. Let's look at another example of a 20 Mbyte drive C. This time the drive has 18 Mbytes of space available. In this case, you can allocate up to 16 of the 18 Mbytes of free space on drive C as a Stacker volume due to the 32 Mbyte disk size limit imposed by DOS 3.3. Allocating 16 Mbytes for a Stacker volume will result in a 32 Mbyte drive since Stacker gives you twice as much storage. ************************* DOS 4.0 & Compaq DOS 3.31 ************************* Under DOS 4.x or Compaq DOS 3.31, the 32 Mbyte volume size limit does not apply. Here, Stacker can accomadate CIFs up to 256 Mbytes, allowing 512 Mbytes of file storage per drive letter. Installing Stacker using these versions of DOS is similar to the installations described in the previous section. Incremental Installation ------------------------ In the following example, we start out with a 40 Mbyte drive C which contains 20 Mbytes of data. Approximately 39 Mbytes of your hard disk will be allocated for a Stacker volume. The size of the resulting drive D is about 80 Mbytes. It has the same 20 Mbytes of data as drive C did and the remaining 60 Mbytes are available for use. System files, including your CONFIG.SYS file and other device drivers loaded before STACKER.SYS, stay stored on the uncompressed portion of drive C. Free Space Installation ----------------------- On the same 40 Mbyte drive from our example, using free space installation you could allocated from 1 to 20 Mbytes of the space on drive C. ********************************* Preparing Your System for Stacker ********************************* System Requirements ------------------- o MS/PC-DOS 3.x or 4.x, or Compaq DOS 3.31 o Hard disk drive o 512 Kbytes RAM for installation o IBM PC, XT, AT, PS/2, or compatible computer o 30 Kbytes RAM for resident device driver Disk Space Requirements ----------------------- There are two separate disk space requirements for installing Stacker. o For Stacker files - During the installation process, you will be asked to select a drive to hold the Stacker files. The Stacker files will be copied from the distribution diskette to the drive you choose. This drive must have at least 360 Kbytes available to hold the Stacker files. o For incremental installation - You will be asked to select a drive to hold your new Stacker volume. This is called the host drive. If you choose incremental installation, the host drive must have at least 1% of its capacity available. Copy-Protected Software ----------------------- If you have copy-protected software, such as Lotus 1-2-3 ver. 2.01, installed on your hard disk, you must remove it before installing Stacker. After Stacker is installed, re-install copy-protected software on the drive of your choice. Microsoft Windows, DESQview, or GEM ----------------------------------- If you are running an operating environment such as MS Windows, DESQview, or GEM, you must exit and return to DOS before installing Stacker. Following installation, you can return to the environment. Local Area Networks (LANs) -------------------------- Network drives cannot be used to host Stacker volumes. If your computer system is connected to a LAN, you will have to log off the network before installing Stacker. The network driver programs may need to be removed from your CONFIG.SYS or AUTOEXEC.BAT files in order to have enough memory (512 Kbytes) to install Stacker. Once Stacker is installed, you can log onto the network. Installing the Software ----------------------- Stacker is supplied with an easy to use program called Install. Install will: o allow you to view the README file o set up the necessary system files to support Stacker o optionally modify your CONFIG.SYS and AUTOEXEC.BAT files o create new compressed volumes o optionally move your existing data to the Stacker volume o optionally swap drive letters so that all software already installed on your system continues to function as it always has ***************** Stacker Utilities ***************** Stacker comes with several supporting utilities, all of which can be called from the DOS command line. However, use of these utilities is not required to realize the benefits of your Stacker compression product. SDIR - How much compression? ---------------------------- SDIR answers this question. It operates much like the DOS DIR command. SDIR displays the compression ratio for the specified file or directory in addition to the normal directory information (filename, size, date, etc.) SDIR can be used on both Stacker and uncompressed disk volumes, and the DOS DIR command still works on Stacker volumes. Format: SDIR [d:][path][filename[.ext]][/P][/W] d: specifies the drive letter on which to run a directory. If not drive is specified, directory information for the current directory is displayed. /P will pause when the screen is full and a prompt will request that you press a key to continue. /W causes the directory information to be shown in a wide display format. The file and directory names are shown, along with an overall compression ratio for the directory. SCHECK - Check a Stacker volume ------------------------------- The SCHECK utility allows you to verify the integrity of the file structures stored on your Stacker volume. You can still use the DOS CHKDSK command to verify the DOS-like properties of your files, but SCHECK goes a step further. Since it understands the details of how your compressed files are stored, SCHECK can detect and repair structural problems that CHKDSK can't. In addition to reporting on the integrity of your Stacker volume, SCHECK displays statistics on the usage of Stacker disk space. Format: SCHECK [d:][/F] d: specifies the drive letter of the Stacker volume to be checked; if no drive is specified, the current drive will be checked. /F tells SCHECK to fix any detected structural problems. SREMOVE - Remove a Stacker volume --------------------------------- Using the SREMOVE utility will cause all data stored on the Stacker vol to be lost. SREMOVE allows you to remove a Stacker volume from your system. If any data is stored on the Stacker volume when SREMOVE is used, a message will be displayed asking for confirmation to continue. Format: SREMOVE d: d: specifies the drive letter of the Stacker volume to be removed from your system. SCREATE - Create a Stacker volume --------------------------------- SCREATE lets you create new Stacker vols. You can also use INSTALL to create more Stacker volumes. Format: SCREATE [d:]\CIF[/S=sss.s][/I=iii.i[/C=d:]] d: specifies the host drive. This is the letter of the drive which will contain the Stacker volume. If no drive is specified, the current drive will be specified as the host drive. CIF specifies the name of the compressed image file which will represent the Stacker volume. You may use any name you like, but we recommend using STACVOL.00n, where n equals the number of existing Stacker volumes. For example, if you used INSTALL to create your first Stacker volume, that volume was named STACVOL.000. To create the next one, name it STACVOL.001. The compressed image file must reside in the root directory of the host drive. It will have the file attributes of hidden, system, and read-only. /S=sss.s specifies that SCREATE is to perform a free space creation and allocate sss.s Mbytes of free space on the host drive to create an empty Stacker volume. The logical size of the Stacker volume will be twice the size specified. /I=iii.i says that SCREATE is to perform an incremental creation and iii.i is the size in Mbytes of the Stacker vol as it will appear to DOS. This option requires that the host drive have at least 1% of its capacity available. If you are using a version of DOS which is not constrained by the 32 Mbyte vol size limit, and you wish to convert the entire host drive to a Stacker vol, you should specify iii.i as twice the size of the host drive. /C=d: can only be used with the /I option. d: specifies the drive letter of the boot drive. This tells SCREATE where to find your CONFIG.SYS file to determine which, if any, device drivers must remain on the host drive. When using SCREATE, you have two options. You can either create an empty Stacker vol, or you can create a Stacker volume and fill it with data from an existing volume. These techniques are free space creation and incremental creation. In free space creation, you allocate a portion of your free disk space for the Stacker volume. For example, suppose you have 10 Mbytes of free space on drive C and you wish to allocate 4 Mbytes to create a new Stacker volume. Using /S=4 will result in an empty 8 Mbyte Stacker volume since you can fit 8 Mbytes of data onto 4 Mbytes of physical disk. Incremental creation, using the /I option, allows you to convert an existing uncompressed volume to a Stacker volume. For example, let's say you have a 20 Mbyte drive C which contains 14 Mbytes of data and 6 Mbytes of free space. Using /I=20, SCREATE copies your existing data from drive C to a new Stacker volume, drive D. As each file is copied from drive C to the Stacker volume, it is compressed and verified, and then the original uncompressed version is deleted. This results in a 20 Mbyte drive D which holds all of the data originally on drive C. After incremental creation, the size of the uncompressed portion of the host drive will always be at least 1 Mbyte. In the above example, you would probably want to use the SSWAP utility to interchange the references for drives C and D. Doing this, any batch files and programs will continue to run as they did before. By using the /C option to specify your boot drive, SCREATE will also look at your CONFIG.SYS file to determine which, if any, device drivers are loaded before STACKER.SYS. These device drivers will be kept on the uncompressed volume, keeping your system running as usual. SCREATE will leave about 1 Mbyte of space on the uncompressed volume so you can add additional device drivers which can be loaded before STACKER.SYS. After you use SCREATE to create a new Stacker volume, you will have to modify your CONFIG.SYS file so that the new volumes can be recognized when you start your system. Add the name of the compressed imag file (CIF) to the DEVICE statement which loads STACKER.SYS. SSWAP - Swap drive letters -------------------------- SSWAP lets you interchange the names of any two drives. This allows you to maintain the drive letter that is most appropriate for your data and the most comfortable for you. If your system is like that of most of users, at least some of your programs and batch files can't run on just any drive. If they were installed on or written for drive C, they need to stay there. SSWAP addresses this issue. If you are using the Stacker installation program to set up compressed volumes and you are performing an incremental installation on drive C, Install will offer to set up a call to SSWAP in your CONFIG.SYS file. This option is offered so that files previously on drive C appear to remain there. SSWAP can be called from CONFIG.SYS or from the DOS command line. When called from CONFIG.SYS, the SSWAP statement must be placed after the DEVICE statement which calls STACKER.SYS. If you don't put it in CONFIG.SYS, you will have to type it on the command line every time you start your system. In CONFIG.SYS: Format: DEVICE=SSWAP.COM d1: d2:[,d3: d4:]... At the DOS command line: Format: SSWAP d1: d2:[,d3: d4:]... d1:, d2: specify drive letters to be swapped. d3:, d4: specify drive letters to be swapped. Creating Additional Stacker Volumes ----------------------------------- After you have used Stacker for a while, you may want to create additional Stacker volumes. You can do this by using INSTALL or SCREATE. Using Install is the easier way. One advantage is that you will not have to perform all of the installation steps that you did the first time. Install will offer new menu selections specifically for creating more Stacker volumes. Another advantage is that your CONFIG.SYS can be automatically updated to include a reference to the new Stacker volume. Editing CONFIG.SYS ------------------ If you chose not to let Install make changes to your CONFIG.SYS file, you will have to add a DEVICE statement so that the Stacker device driver, STACKER.SYS, can be loaded when you start your system. If you use SCREATE instead of the installation program provided with Stacker, you will need to edit your CONFIG.SYS file so the new Stacker volumes will be recognized at startup time. Refer to the definition of the CIF parameter in the DEVICE statement format below. The format of the DEVICE statement for the Stacker device driver is as follows: DEVICE=[d:][path]STACKER.SYS[/B=xxxx][/M=nnn] CIF1 [CIF2]... d: specifies the drive letter of the drive containing the Stacker device driver path is the path on drive d: in which the Stacker device driver resides. This path must point to an uncompressed disk volume. Stacker volumes don't exist as drive letters until the Stacker device driver has been loaded. /B=xxxx specifies the base address of the 16 Kbyte memory window used by the Stacker coprocessor card. The hardware installation program, HINSTALL, aids you in selecting this address. /M=nnn specifies the amount of system memory, in Kbytes to be allocated as a disk cache. Using a disk cache can dramatically improve the performance of your hard disk. The resident size of STACKER.SYS will be increased by the size of the disk cache you choose. CIF1 is the name of a compressed image file. This file must reside in the root directory of the drive hosting the Stacker volume. If you used Install to create your Stacker volume, make the modifications as directed during installation. If you created a new image file by using SCREATE from the command line, add the image file name you used there to the end of the current list of image files. ************************************ Loading STACKER.SYS into High Memory ************************************ Stacker uses a modest amount of resident memory. It requires about 30 Kbytes for the Stacker Software Version. You can load the Stacker device driver into high memory, freeing up valuable memory space for your other applications. Below we have provided guidelines for using four popular memory management programs for Intel 80286 or 80386 systems that allow you to use this feature with Stacker. General Notes ------------- For this discussion, each memory manager product includes two parts: a memory management device driver and a utility to load device drivers into high memory, load-high. The DEVICE statement for the memory manager must precede the DEVICE statements for the laod-high utility and STACKER.SYS in your CONFIG.SYS file. The memory manager device driver, the load-high utility, and STACKER.SYS must reside on an uncompressed drive and not on a Stacker volume. You may need to specify additonal parameters depending on your system configuration. Refer to the manuals that came with your memory manager for details. 80286 Systems ------------- In QRAM from Quarterdeck Office Systems, LOADHI provides the load-high function for systems equipped with hardware support for EMS 4.0. If the DEVICE statement reads as follows: DEVICE=C:\STACKER\STACKER.SYS C:\STACVOL.000 then change it to: DEVICE=C:\QRAM\LOADHI.SYS C:\STACKER\STACKER.SYS C:\STACVOL.000 MOVE'EM is from Qualitas, Inc. and performs the load-high function. MOVE'EM is for systems equipped with hardware support for EMS 4.0. If the DEVICE statement reads as follows: DEVICE=C:\STACKER\STACKER.SYS C:\STACVOL.000 then change it to: DEVICE=C:\MOVE'EM\MOVE'EM.SYS PROG=C:\STACKER\STACKER.SYS C:\STACVOL.000 80386 Systems ------------- In QEMM-386 from Quarterdeck Office Systems, LOADHI performs the load-high function. If the DEVICE statement reads as follows: DEVICE=C:\STACKER\STACKER.SYS C:\STACVOL.000 then change it to: DEVICE=C:\QEMM\LOADHI.SYS C:\STACKER\STACKER.SYS C:\STACVOL.000 In 386MAX from Qualitas, Inc., 386LOAD performs the load-high function. If the DEVICE statement reads as follows: DEVICE=C:\STACKER\STACKER.SYS C:\STACVOL.000 then change it to: DEVICE=C:\386MAX\386LOAD.SYS PROG=C:\STACKER\STACKER.SYS C:\STACVOL.000 ************* Compatibility ************* Copy-Protected Software ----------------------- Copy-protected software, such as Lotus 1-2-3 version 2.01, is compatible with Stacker. Before installing Stacker on a host drive containing copy-protected software, follow these steps: o Uninstall any copy protected software o Install Stacker o Re-install copy protected software on any drive Microsoft Windows 3.0 --------------------- Stacker is compatible with Microsoft Windows 3.0. However, you must exit from the Windows environment before installing Stacker. After installing Stacker, you can return to Windows where you can make use of your new Stacker volumes. Disk Utilities -------------- Preservation of the standard DOS architecture allows Stacker to be compatible with most commonly used disk utilities such as PC Tools Delux, The Norton Utilities, Norton Disk Doctor and Unerase. Disk Defragmenter Programs -------------------------- Disk defragmenters/optimizers/reorganizers generally improve the performance of your hard disk by rearranging the files on your hard disk so that they are stored contiguously. The improved performance comes from eliminating the need to collect the fragments of your files which may have been scattered all over your hard disk. Since files are stored differently on Stacker volumes, this type of program will not have the same effect. In fact, the result of using a defragmenter program will be to fragment your Stacker volume and thus actually decrease performance. You can still realize the benefits of a defragmenter program by running it on a drive which hosts a Stacker volume. Disk Caching Programs --------------------- A disk cache is another class of disk utility which improves the performance of your hard disk. This improvement is achieved by keeping a copy of frequently used data in a portion of your memory called a cache. Once data from your hard disk is in the cache, it can be used again directly without making t with several of the most popular disk caching programs and has been found to be compatible. ********************* Upgrading Your System ********************* DOS 3.x to 4.x -------------- MS/PC-DOS versions starting with 4.0 and Compaq DOS 3.31 free your system from the 32 Mbyte volume limit imposed by earlier versions. As a result, you will be able to create larger Stacker volumes by using DOS 4.x to create partitions larger than 32 Mbytes. See your DOS manual for specific instructions on creating partitions volumes larger than 32 Mbytes. If you are considering a change from DOS 3.x to 4.x, we recommend that you do it before installing Stacker. If you have already installed Stacker, you will have to remove Stacker completely and reinstall it after your conversion to DOS 4.x. Adding a New Hard Disk Drive ---------------------------- You can add additional hard disk drives to your Stacker equipped system at any time. Follow the manufacturer's instructions for installation. The only effect this will have on Stacker volumes is a possible re-assignment of disk drive letters. DOS assigns drive letters at system startup as needed. If your new hard disk drive can be recognized automatically, then your Stacker drive letter will be moved down the alphabet in proportion to the number of new letters added by the installation of the new hardware. Some hard disk drives require that a device driver be added to your CONFIG.SYS file. Changes in drive letter assignment depend on whether the hard disk driver is called before or after STACKER.SYS in your CONFIG.SYS file. You can control the assignment of drive letters by calling STACKER.SYS either before or after other hard disk device drivers in CONFIG.SYS. The only restriction is that STACKER.SYS must appear in your CONFIG.SYS file before any drivers for disks which will host Stacker volumes. **************** Removing Stacker **************** There may come a time when you want to remove Stacker from your system. You can remove individual Stacker volumes or remove Stacker completely. When data is removed from the Stacker environment, it gets bigger. Partial Removal --------------- This will describe how to remove one or more Stacker volumes from your system. Follow the steps below: 1. Back up essential data. Back up any data that you want to keep which resides on your Stacker volumes. If you have a full 20 Mbyte Stacker vol and you want to keep all of your data intact, you will need about 40 Mbytes of uncompressed storage to hold your data while removing Stacker. After removing Stacker from your system, you will have only the 20 Mbytes of space that originally existed before installing Stacker. 2. Run the SREMOVE utility. SREMOVE allows you to remove a Stacker volume from your system. If any data is stored on the Stacker volume when SREMOVE is used, a message will be displayed asking for confirmation to continue. Format: SREMOVE d: d: specifies the drive letter of the Stacker voolume to be removed from your system. 3. Edit your CONFIG.SYS file. Change the DEVICE statement which loads the Stacker device driver, STACKER.SYS. For example, if your system has one physical disk drive, drive C, and two Stacker volumes, drives D and E, the DEVICE statement may look like the one shown below. DEVICE=C:\STACKER.SYS /B=c800 C:\STACVOL.000 C:\STACVOL.001 If you wish to remove drive D, you should remove the first image filename, C:\STACVOL.000. Similarly, if you wish to remove drive E, you should remove the second image filename, C:\STACVOL.001. Note that if you remove C:\STACVOL.000, the next time you start your system, C:\STACVOL.001 will become drive D. Delete all SSWAP statements which reference the removed drive. Complete Removal ---------------- This will describe how to completely remove Stacker from your system. Follow the steps below: 1. Back up essential data (see above) 2. Run the SREMOVE utility. (see above) 3. Edit your CONFIG.SYS file. Remove the DEVICE statement for STACKER.SYS. Also remove all SSWAP statements in your CONFIG.SYS file. 4. Edit your AUTOEXEC.BAT file. The PATH statement may have been modified to include a reference to the directory where Stacker files reside. If this is the case, edit the PATH statement by removing this reference. 5. Delete files. There may be a subdirectory on drive C where the Stacker system files reside. This directory will usually be called \STACKER. Delete these files and the STACKER subdirectory. ********************* Questions and Answers ********************* Q: How does Stacker fit more data onto my disk? A: Stacker fits more data onto your disk in two ways. First, Stacker saves space by replacing repeated sequences of bytes it finds in your file with tokens that point to a previous occurrence of the sequence. Since the tokens take less space than the redundant sequence of bytes, a reduction in the file size occurs. This process of removing redundancy is called lossless data compression. It is so named because no data is lost in the process. The second way Stacker uses less of your disk to store small files (less than 2 Kbytes) is by allocating your disk space in sectors (512 bytes) instead of clusters (usually 2 Kbytes or more). This means that a small file of 200 bytes will take up only one sector (512 bytes) instead of an entire cluster (2 Kbytes). Q: Is Stacker compatible with all versions of MS-DOS and PC-DOS? A: Stacker works with all versions of MS-DOS and PC-DOS 3.x and 4.x. This includes Compaq's own 3.31 version of DOS, which breaks the 32 Mbytes barrier. Stacker is also compatible with all DOS commands such as DIR, COPY, XCOPY, and CHKDSK. Q: Is Stacker compatible with disk caching programs? A: Yes. Stacker has been tested with the PC Tools Deluxe and Super PC-Kwik disk caching programs and has been found to be compatible. Stacker includes a minimum amount of caching in the Stacker DOS device driver. Using a disk caching program in addition to Stacker can increase overall disk performance. Q: Is Stacker compatible w/ disk utility programs such as Norton Utilities and PC Tools? A: Yes. Because Stacker is completely compatible with MS-DOS, you can use utility programs that allow you to undelete files and analyze your hard disk. While the use of a DOS defragmenter or optimizer such as the PC Tools COMPRESS utility or Vopt will not have a positive effect on the access time, it will not harm a Stacker volume. Q: How long does it take to install Stacker on my computer? A: Installation consists of plugging in the hardware (if you purchased the Stacker Coprocessor Version), loading the software driver, and then creating Stacker volumes. Installing the Stacker coprocessor card is simple because there are no jumpers or switches to worry about. The Stacker coprocessor card does not use DMA, does not use interrupts and does not require base I/O address. A simple installation program is used to allocate a 16 Kbyte memory window above 640 Kbytes. Installation of the Stacker device driver takes less than five minutes. Q: Does Stacker works with Microsoft Windows 3.0? A: Yes. Stacker is completely compatible with Microsoft Windows 3.0. Q: Do I need to reformat my hard disk drive in order to install Stacker? A: No. You do not have to reformat your hard disk. In fact, the Stacker volume is stored as a file on your MS-DOS volume. This file has the system, hidden, and read-only attributes set, and is therefore invisible to the normal DOS DIR command and protected from accidental erasure. Q: Can I use Stacker with devices other than a hard disk, such as floppy disks, Bernoulli Boxes or RAM disks? A: No. Stacker is designed and optimized for useonly with non-removeable Winchester hard disks. Future versions of Stacker will support removeable media such as floppy disks and volatile storage such as RAM disks. Q: Does Stacker work with all types of hard disk drives, including ST-506, IDE (AT Bus), SCSI, and ESDI? A: Yes. Stacker has been tested with all types of disk drives and even works with OEM disk device drivers. Q: How will Stacker affect the disk access performance of my computer? A: Our benchmarks show that the speed of most disk-intensive applications will not be adversely affected. Read-intensive operations are faster in most cases with the Stacker compression coprocessor installed. Performance using the Stacker Software Version will vary depending on the speed of your microprocessor. Q: Do I have to anything to my existing programs or data files in order to utilize Stacker? A: No. Once Stacker is installed, you should use your computer and hard disk as you normally would. The only difference you will see with Stacker installed is a doubling in the effective capacity of your hard disk and a decrease in the time it takes to read data from that drive. Q: Am I guaranteed to get a 2:1 increase in capacity on my hard disk regardless of the types of files I store on it? A: It is possible to achieve less than a doubling of capacity if your hard disk contains many files that are not very compressible. However, we have sampled many actual users' hard disks and have determined that a 2:1 increase in capacity is average. We are so sure that most people will be satisfied with the increase in capacity they gain by adding Stacker that we offer a 90-day money- back guarantee. Q: How can I tell how much additional capacity Stacker will provide on my hard disk? A: Once you have installed Stacker, you can run the Stacker directory command called SDIR. SDIR is like the DOS DIR command, except that it reports the compression ratio that Stacker has achieved for each file and for the entire directory. An average compression ratio of 2:1 means you will be able to achieve twice the capacity on your hard disk. You will be able to determine the amount of space available on your Stacker volume by running CHKDSK as you normally do under DOS. Q: Are there any types of files that I should not store on a Stacker volume? A: No. You should use your hard disk just as you normally would. Q: Can I load the Stacker device driver out of the way in high memory using a memory manager such as QEMM-386? A: Yes. You may use memory manager utilities to load the Stacker device driver above the DOS 640 Kbyte limit in order to conserve DOS-accessible memory for large programs. xXxXxXxXxXxXxXxX BROUGHT TO U BY ^FAUST^ xXxXxXxXxXxXxXx /\ / / ________ /__\/\_______\ ___( __ \/|_/|_/|_/|_/|_/|_/|_/|_/|_/|_/|_/|_/|_ ( __ |=|=| _| __________________________________ \ || _\ |=|=|1991 __| ___WE_*ARE*_THE_CUTTING_EDGE !!___O) -- ||/ \|=|=| ___| ______________________________________\ || | __________// |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ |/ ||___/___________/ (____/ xXxXxXx INFERNO DATA HAVEN : DIE YOUNG, STAY PRETTY xXxXxXx