|★ APPLICATIONS ★ DISQUE ★ DISC POWER ★|
|Super Power - Disc Power ROM (Computing with the Amstrad)||Applications Disque|
NOW that ROM expansion boards have started appearing for the Amstrad, several companies are releasing software on ROM.
One of the first few ROMs on the market is Disc Power by Micro Power, a disc utility designed for the CPC664 and disc-based CPC464s.
The ROM is supplied in a video cassette-type box with an 18-page manual and a shorting link for the Superpower ROM card.
Once installed, Disc Power can be called up with the command |DP, after which a menu with ten options is displayed. These are shown in Figure I.
Each option is selected simply by pressing the key corresponding to the reference character at the side of the option.
The first menu option, specifically designed to help recover deleted files from disc, loads the directory of the disc into a 1k buffer at location &A000 then enters the Edit mode - option 5.
Option 2 permits any sector from any track to be edited in the same way as for the directory. Disc Power also uses the buffer for several other utilities, as we'll see.
Figure I: Main Menu
Once the desired sector has been successfully edited, it can be saved back to disc using option 6 - Write Sector to Disc.
The editing screen, which nearly all the commands are based on. consists of a hex and Ascii dump of a selected area of memory, the start of which can be changed by either scrolling through memory using the cursor keys or by entering a totally iew base address. For st menu options this will be &A000 -Disc Power's own 1k buffer.
Editing is a simple task and involves positioning the cursor, using the arrow keys, at the location to be edited, and entering the new value. This can be done in either Ascii or hexadecimal.
The altered bytes are not written to memory until the Enter key is pressed on the same line.
If during editing you require a dump of the screen you can do so simply by pressing the Tab key.
Menu option 4 allows a selected ROM to be examined. Once a ROM has been chosen from a given list, the first 1 k of it is copied into the buffer at &A000.
The editing mode is now called up and the ROM can be examined. The actual address of the ROM. as opposed to the buffer address, is shown on the top line of the screen. The rest of the ROM can be read into memory by pressing the appropriate cursor arrows in conjunction with the Ctrl key.
Option 3 loads 1k from the start of any file on disc into the buffer and enters the editor. The start track and sector of the file are calculated by Disc Power and displayed at the top of the screen.
The disassemble/tabulate option allows any section of memory to be displayed in the selected format on the screen or printer. This permits programs in ROM, RAM or on disc to be examined - assuming they've been copied into the buffer beforehand.
Pressing a key between 1 and 9 will display lines in that multiple of six at a time. In addition to this continuous output can be produced.
The disassembler mode can also be made to follow all jumps. This means that instructions such as JP. JR and CALL- can be followed. This is extremely useful for debugging simple routines.
More-complex programs would have to be traced using a machine code monitor of some kind. Even so, the disassembler trace is very useful.
The search memory option allows an Ascii string or sequence of hex bytes to be located within a specific area of memory. The search string can contain a wildcard character - ?.
Thus a string search for J?K would find any string of three letters which starts with J and ends with K - such as JAK and JUK.
The addresses of all occurrences are then printed ready for interrogation.
Menu option 9 offers various utilities mainly for use with discs. These include a formatter, backup routine, simple calculator and a very clever disc/file map - the formatter and backup options don't require a CP/M utility disc.
The disc/file map produces a pictorial diagram of all 40 tracks of the disc and highlights specific areas. For example, a disc file can be selected and a diagram will be produced highlighting the tracks and sectors containing the file.
It can also show areas containing files which have been erased.
These can then be loaded from disc into memory and examined using the disc editor.
Provision has also been made to call routines in background ROMs by use of the bar commands. Foreground ROMs can also be entered but all data in memory will be lost.
The last two utilities allow files to be transferred between disc and memory.
The final option in the main menu permits the screen format to be altered. This allows a 40 or 80 column screen with either 12 or 24 lines.
In addition to the screen format the screen inks can be altered - specially designed for those of us who like the Amstrad's pretty colour palette.
The only real moan I have, though, is that the 18-page manual is poor and lacks informative examples - nice ROM, shame about the manual.
Otherwise. Disc Power is well presented and contains some useful utilities. It would have been nice if they had included a disc string search and an option to transfer programs from tape to disc and vice versa, but you can't have everything.
All in all, Disc Power is well worth considering.
Kevin Edwards , CWTA