Software Review: SqueeZ~88

Squeeze is a new application for the Z88 from Rakewell - authors of that marvellous book, Z88 Magic. This is, I believe, the first software package that Rakewell have produced. As well as being able to buy Squeeze as a stand-alone package from Rakewell or other Z88 dealers, you can also get it included with the RangerWorld multi-application chip. (See last issue's Newslines for more details.)

What is the point of Squeeze? It really has two main functions. Primarily, Squeeze can be used to process files held in your Z88 to make them use up less valuable RAM. This is ideal if you store a lot of files on your Z88 and are constantly running out of memory, because with Squeeze, you can compress all the files to release some memory, and un-squeeze the files when you want to work on them.

The other major use of Squeeze, which will probably only matter if you use your machine in business, is file security. As we all know, the Z88 has no protection to prying eyes - anyone can switch on the machine, and look at all your secrets.

Squeeze allows you to select a password before you compress a file, and as the program processes the file it also scrambles it according to the password you have chosen. Once a file has been scrambled in this way, it is totally secure, and even if someone took a copy of the file, they could never decode it unless they knew your original password. You do know your password (don't you?), and you simply enter this when you come to un-squeeze the file, and hey presto!

Rakewell's Squeeze for the Z88 uses a standard form of file compression, which means the compressed files it produces can be un-squeezed by a compatible program on another computer. To this end, Rakewell can supply a PC version of Squeeze. Using this, you can compress files on the Z88, transfer them using PC Link, (or my favourite, RangerLink), and then un-squeeze them as required on the PC. The advantages of working like this are many - the files take up less space on the Z88; because they are smaller they transfer more quickly to the PC; and of course they also take up less space on the PC!

Once Squeeze has been installed on your Z88 (which must have at least 128k expansion in slot 1, by the way), it can be selected using []U. (U for what, I ask?)

You are then presented with three windows across the Z88 screen, (a la RangerLink or Ranger's DiskFiler, which betrays the origin of the software's author.) The small window on the left gives all the commands, the centre window shows a directory of the current device/directory, and the right-hand window shows the Squeeze directory, which is by default where squeezed files are placed. This can be altered if desired, but the manual points out that it is wise to keep squeezed files in a separate directory to avoid getting them confused with un-squeezed files.

Using Squeeze is very simple. Files in either window can be marked either singly, selectively, or all together as a whole directory, and selecting the command you require does the rest. The program gives you an on-screen "running commentary" of its progress, including how many more files it has got to process after the one it is currently acting on. Squeezes files will have the same filename as the original version, but the second letter of the filename extension will be changed to a Q. (If you squeeze a file which has no filename extension, Squeeze adds its own - ".ZSQ".

The manual is, by the way, excellent. So often software is accompanied by a few photocopied sheets of "instructions", and even if the content is reasonable, so often the presentation leaves a lot to be desired. Not so with this program - the manual is an A5 horizontal format booklet of 35 pages, properly typeset and printed. It's about time one or two other Z88 software suppliers took a leaf out of Rakewell's book (or should that be manual?) when it comes to documentation. Because it is really essential to use directories on the Z88 if you are using Squeeze, the manual even gives the reader a whirlwind guide on how directories work.

One interesting point that the manual does mention is that squeezing a file may make it bigger! Because of the way the squeezed files are stored, short files under 2k might acutally end up bigger than they started out, and because of this Squeeze will not normally even try and compress any file shorter than 512 bytes.

I won't go into any detail on how Squeeze works its magic, as following this review is an article by Andy Berry at Rakewell, who explains how these compression programs work far more clearly than I ever could!

A couple of interesting "bonus" commands are included in Squeeze. "Look at Z88 file" allows you to view files within Squeeze - very useful for checking on the contents of PipeDream files without having to load them into PipeDream first. The other useful addition is a complete re-work of the Z88 Copy command. If you have ever tried to copy groups of files from one directory to another, you will know how confusing and difficult the Filer's Copy command can be. In Squeeze it is purely a case of selecting the two devices and directories you want to deal with, marking the files you want to copy, and pressing enter!

I was pleasantly surprised by the speed of Squeeze in use. Vic Gerhardi of Rakewell had told me in the early stages of the programs development that he was hoping the final program would be quite quick at un-squeezing files, but that he expected it to be fairly slow at the initial squeezing. This, I'm glad to say, is not the case. The program processes the files impressively quickly, and more often than not, the resulting compressed file is indeed smaller than the source file. The exact amount of compression varies from file to file, and as you will read in Andy Berry's article, the amount of compression is really dependant on the content of the original file. To give you some idea of the speed and effectiveness of Squeeze, below I have compiled a table which illustrates typical values of time and compression for different types of files:

File           Length           Time to
Type        Before  After   Squeeze  Un-Squeeze
PD Text      13305   8635   12.1sec      6.8sec
PD Text       2285   1683    5.2sec      1.8sec
PD Spread     3172   1800    5.7sec      2.1sec
BASIC Prog   27037  21166   29.7sec     11.0sec

As you can see from the above table, the file compression that Squeeze achieves is quite good, but does vary from file to file. In general, large text files seem to give the best reduction in size, and BASIC files the least. While testing Squeeze and in the time since then when I have actually been using it, I must have processed about 1 megabyte of files with the program, and so far it has worked faultlessly, and has always been able to recover the squeezed file back to its original state.

SqueeZ~88 costs £39.95 + VAT + carriage.

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