#Titel Hard- & Software / Software / DiskExpander #Logo gadget14:pinsel/AG.Hard&Soft #Font Frankfurter 16 #C31 /// Usenet Review: DiskExpander --------------------------- #Font topaz 8 #C21 By Njaal Eide (njaale@dhhalden.no) (reformatted by Holgi) #C20 PRODUCT NAME #C21 DiskExpander ("DE") #C20 BRIEF DESCRIPTION #C21 A utility to expand your storage capacity on floppy and hard disks. #C20 COMPANY INFORMATION #C21 Name: Stefan Ossowski's Schatztruhe Address: Veronikastrasse 33 45131 Essen Germany Phone: 0201/788778 Fax: 0201/798447 Email: stefano@schatztr.adsp.sub.org #C20 LIST PRICE #C21 $ 30,- #C20 SPECIAL HARDWARE AND SOFTWARE REQUIREMENTS #C21 Any Amiga with Kickstart later than 1.2. At least 1 meg memory is highly recommended. #C20 COPY PROTECTION #C21 DE is copy-protected. But as the original disk is only used when you install DE, this is not a problem at all. Serious changes in your system, or in DE's configuration, might make it necessary to use the original disk again. The disk also contains a unprotected utility that lets you recover your compressed data if your DE disk should get damaged. #C20 MACHINE USED FOR TESTING: #C21 Amiga 4000/030, 6M RAM. 80MB Seagate hard drive, 250MB Western Digital hard drive. #C20 INTRODUCTION #C21 If you ever run out of storage-space for your files, you are faced with three alternatives: buy more storage-space, delete files, or use more efficient storage methods. DiskExpander is a product that takes the latter approach to solving this problem. DiskExpander (or "DE" for short) is a pro- gram that gives you on-the-fly compression/decompression of files. This means that when DE is installed on a device, all files get compressed when saved and uncompressed when loaded. This process is totally transparent to all applications, as they will not even know that they are loading/storing compressed data. This is a really great concept, but as with everything great, it's got a catch to it: disk access gets slower (in most cases) and can be demanding in memory terms. I will discuss this in more detail later on in the review. #C20 PACKAGE #C21 When I first opened the DE box, I got a little surprised that it contained no less than three disks. Shouldn't this be a storage expander and not a storage filler? Upon further inspection, I found that one of the disks is a demo version of TurboCalc v2.0 and the other two are identical copies of DE. I guess this was due to a packaging mistake at the manufacturer, but a backup is nice anyway. Furthermore, the box contained manuals in both Ger- man and English. The German manual was included probably because the English manual was not completed. The latter came in the form of a bunch of loose A4 sheets; but by the time you read this, it should have been made into a pro- per manual. Anyway, the content of it turned out to be clear and informa- tive: no problems here. If it wasn't for the single phrase "1.3 oder 2.0 style", I (a Norwegian) could have been fooled to believe it was written by an Englishman. #C20 INSTALLATION: #C21 DE uses the brilliant Installer program from Commodore, and the installation works nicely indeed. The only problem occurs when you are per- sonalising your DE disk, as the installation script doesn't check the pro- tection state of your disk. So whatever you write will get lost if your disk is write-protected. #C20 CONFIGURING DE #C21 When you have successfully installed DE on your hard disk, the first thing you ought to do is to configure it as you please. There are several ways to do this. You can manually edit your startup-sequence, or let a con- figuring program do it for you. DE also supports various tooltypes in a Pro- ject icon. So if you please, you can place DE icons, one for each device, in the WBStartup drawer (Workbench 2.0 or later). I do not recommend the latter approach, as it seems unreliable (DE doesn't recognise all the tooltypes that it supposedly should). I also had problems using this method on more than one device at a time. What happens is that DE functions like an on/off switch. Run it once, and DE activates. Run it again and it dies. This would have been nice if DE checked the state of the device you are trying to acti- vate. Instead, DE checks only if it is active on ANY device, and if it is, then it disables itself completely. (Remember, this is only a problem with two or more project icons in WBStartup. With scripts, there are no pro- blems.) DE doesn't contain a fixed number of compression algorithms built into the program. Instead, it uses external libraries for compression purpo- ses, including the widely available XPK standard and others. The use of external libraries lets the user choose which algorithm is most suitable for his/her needs. To add a new packing method, you just add a new library. A user with little memory could choose a library which uses little of it. A user with a fast, powerful machine could choose an algorithm that has very good compression ratio, but is too slow on a less powerful machine. There are libraries optimised for most needs (speed, compression-ratio, certain file types, memory etc.), so most users will find something appropriate. Lots of external libraries are supplied, and their pros and cons are dis- cussed in the manual. Still, it seems like SOS haven't been able to keep up with the development of new XPK-libraries. I found that I had a newer ver- sion of the XPK-library 'NUKE' on my hard disk than on the DE disk. Not a big deal anyway as new libraries will be supplied to registered users. Every other program that I have with XPK support expects to find the XPK libraries in LIBS:compressors. DE expects to find then in LIBS:. This means that I now must store them in both places and shows poor attention to detail on SOS behalf. I tried the DOS-command #C10 ASSIGN LIBS: SYS:libs/compressors ADD #C21 which should assign both directories to LIBS, but this doesn't seem to work with any program. Is this a bug in AmigaDOS? #C20 IN USE #C21 Now we have come to the most interesting part. How is actually DE in everyday use? I must admit that DE in the beginning was a real pain. Pro- grams was either crashing like mad, or they refused to load. I was preparing for a long and harsh letter to the publisher. But by coincidence I changed the settings for DE, and every problem vanished. Since then, I haven't had a single problem with DE at all. This means six weeks of solid use, and not a single crash due to DE. Excellent. To save other users from the problems I had, here is what I found: There are two options in DE called 'No Examine' and 'No ExNext.' DON'T USE THEM! These two options determine how AmigaDOS finds the size of files. If used, AmigaDOS calculates the physical size of the file. If not, AmigaDOS calculates the uncompressed size. For a user (me at least), it is more inte- resting to know the physical size than the virtual. For the Amiga, it's definitely not. My theory why this is essential is as follows. When a pro- gram loads a file, it first checks its size and allocates that amount of bytes in memory. What happens then is that the uncompressed file occupies more space than allocated, causing all sorts of problems/crashes. So remem- ber to use only 'Examine' and 'ExNext.' #C20 BENCHMARKS #C21 I started out making some benchmarks that measured loading/saving times with and without DE installed. But I've come to the conclusion that benchmarks don't say much. It all depends on how powerful a machine you have, how many tasks are running simultaneously, what pack library you are using, your hard disk interface, file size, etc., etc. All I can say is that my experience with DE is highly enjoyable. With my setup, the increased loa- ding time from hard disk is just noticeable, and only with large files. With floppies, loading time actually decreases. On average you will save about 30-40% disk space with the most effi- cient pack library. For text files, expect 50-70% savings, and for pre- viously packed files (like GIF, JPEG, LHA etc.) you will not save a single byte. So if you have a hard-disk full of packed pictures, you will not save much. If you on the other hand are a programmer with lots of include files and AutoDocs, then your savings will be enormous. So take a look at your files before you decide if DE is for you. #C20 INCLUDED UTILITIES #C21 With DE comes a utility that lets you pack or unpack a complete par- tition. This is useful when you are installing DE for the first time, or if you want to change pack libraries or remove DE. Another utility inspects the files of your choice and gives you various information like compression level, pack library used, file size, etc. #C20 IMPROVEMENTS #C21 I'd really like to see DE transformed into a commodity. Right now, I find it a little cumbersome to change parameters for DE. I guess this was dropped in order to keep compatibility with Kickstart 1.3 (why do publishers still make productivity software for 1.3?). It would also be nice to be able to use different pack libraries on different directories or assigned drives. Right now, all files on the entire partition use the same algorithm. It should also been possible to mark files that DE should not compress. That way it would be much safer to install it on a boot partition. Right now, you can end up in great trouble if you compress some of the files DE needs for itself. I would also like to see DE supporting RAM: and PC0:. For some rea- son, RAM: is only supported on machines with Kickstart 1.3. #C20 COMPARISON TO OTHER SIMILAR PRODUCTS #C21 There are at least two similar products as shareware called EPU and XFH. Both gives similar compression results as DE as they use the XPK stan- dard, but they are very unstable. I have tried them both, but I had to give them up. By the way, EPU is written by the same author as DE. #C20 CONCLUSION #C21 When you first have got it properly installed, DE is really good. I really recommend it. For those that really think loading times are impor- tant, why not compress only the files you don't use very often? #C20 COPYRIGHT NOTICE #C21 This document is copyright 1993 Njaal Eide, but freely distri- butable. #C10 E-mail: njaale@dhhalden.no Njaal Eide Harreschousvei 31 1300 Sandvika Norway Phone: NORWAY-67548247