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written by Maurice Hawes / SUC/UK
Source: SUC-magazine January 2004, Volume 23, Number 3, pp. 20 - 21 
Sharp Users Club - MZ-800 Section - FLDOS-800

As reported in the Editorial, FLDOS-800 came to us on a 5¼" disk from Terry Daly in Australia. The disk boots as normal and displays the following screen ( the top line being 'normal' and the rest inverted ). Note that on this screen, as on most other screens, there are one or two words that are miss-spelled or left in German:-

FLDOS 2.x Boot Loader © 1986 by nibbelsoft & sds Computer Service 5568 Daun
Commands: Press numberkey 1-8 to select File

Eingabe ( flashing prompt for key input 1 - 8 )

ESC = Exit to FLDOS
  Load Size Auto
1 FOR -> Tutenchamun (if run, displays the date 1985)
  2000 7200 2000
2 FOR -> Zexas (if run, displays the date 1985)   2000 7000 2000
3 FOR -> Flappy (If run, displays the date 1984)   1E00 AD00 1E00
4 FOR -> Moty (if run, displays the date 1985)   1200 BD00 12BC
5 FOR -> Nakamoto (no date)   2C00 8800 2C00
6 FOR -> Puck-man (no date)   7E00 4200 8FE0

From the above it appears, at first sight, that this is a simple 'loader' system designed to facilitate the easy and rapid loading of machine-code games programs, with a maximum capacity of 8 games. However, if you press 'ESC' instead of 1 - 8, the top 2 lines of the display change and an additional message 'Stopped by User' appears, to indicate that a new Menu is on offer and the games ( though still listed on screen ) are no longer accessible:-

FLDOS 2.x © 1986 by Frank Lauter nibbelsoft & sds Computer Service 5568 Daun
Commands: F-ile IO / D-rive / E-dit Sector / B-oot Disk / M-onitor Start

Eingabe ( flashing prompt for key input F, D, E, B or M )

Stopped by User

The options on the 2nd line above, which may be thought of as the 'Main Menu', behave as follows:

F changes the 2nd line of the screen to read as follows:-

Commands: D-ir / L-oad / S-ave / E-rase File / R-ead-> W-rite Sectors / Q-uit

D prompts for Drive numbers 1 - 4 ( i.e. it sets the default drive for future commands )

E - prompts to insert the DOS masterdisk and press any key, then changes the 2nd line to read:-

Commands: R-ead Absolute Sector / F-ile Begin / Q-uit

B - Boots the Disk in Drive A

M - Returns to the Monitor Screen

The 'Sub-Menus' offered by options F and E above are described on the next page.

Sub-Menus in FLDOS-800

1) Main Option 'F' offers the following 'Sub-Menu' on the 2nd line of the screen:-

Commands: D-ir / L-oad / S-ave / E-rase FiIe / R-ead-> W-rite Sector / Q-uit

D-ir displays the directory of the disk in the default drive ( which may be a Sharp Basic disk )

L-oad - asks for a filename, and then loads the file from the default disk into memory. When the load is completed you are offered the following options:

Commands: CR = Accept Data / W-rong File / M-odify Data / Q-uit

S-ave - asks for a FILENAME and the START, LENGTH and AUTOEXECUTE parameters ( in HEX ), and then saves the file in memory on the default disk

E-rase - asks for a filename and then erases the file on the default disk

Read Sectors - asks for the 'Abs Sector', RAM ADDRESS and LENGTH, and then reads the requisite number of sectors off the disk and puts them at the RAM ADDRESS specified, and says 'File Loaded'

This command asks first for the start of a file on disk, then where to put it in RAM, then for its length i.e. it is designed to load a specific file into memory, albeit in a complicated way. At the moment I cannot see the point of this command, but perhaps, given time, the light will eventually dawn.
( Note by Download FLDOS 1.x from my site and read the German Manual ).

Write Sectors - asks for the 'Abs Sector', RAM ADDRESS and LENGTH, and then writes the requisite number of sectors out of memory onto the default disk, and says 'File Saved'

This command asks first where to put a file on a disk, then for its START address in RAM and its SIZE i.e. it is designed to save a specified area of RAM to a specified position on a disk. This is a VERY DANGEROUS OPERATION and again, I cannot really see the point of it at this moment in time.
( Note by Download FLDOS 1.x from my site and read the German Manual ).

2) Main Option 'E' offers the following 'Sub-Menu' on the 2nd line of the screen:-

Commands: Read -> A-bsolute Sector / File Begin / Quit

Absolute Sector - asks for the absolute sector address on the disk ( N.B. there are 16 sectors per track, and the 1st sector on track 00 is sector 0000H, the 1st sector on Track 01 is sector 0010H, the 1st sector on track 02 is 0020H, etc., etc.) The chosen sector is then displayed on screen and the 2nd line on the screen changes to:-

Commands: N-ext / L-ast / Modify / U-pdate / Read / Z-eichensatz 2 / Quit

Most of the above options are obvious i.e. Move to the NEXT sector, Move to the LAST Sector, MODIFY the current sector in RAM, UPDATE the current sector on disk, and READ the current sector back in from the disk to check that it has been modified correctly. The only unusual command is Z-eichensatz 2, which toggles the 'ASCII equivalent' section of the display on the R.H. side of the screen between the 1st and 2nd Character Sets.

Summary of FLDOS-800

There is nothing quite like this system on any other MZ machine ( except perhaps for 'QDOS' on the MZ-80K, which can load M/C programs in a similar way, but does NOT have any of the other extra features ).

The games themselves are quite sophisticated, and the disk as a whole demonstrates ( again ) that there was much more support for the MZ-800 in Germany than there was in the U.K. But the extra features do not offer anything very new, as we have essentially the same facilities available in our own DISKEDIT program for the MZ-800.

The disk format is the same as SHARP BASIC and it may be copied by FDCOPY. There is one point to watch - the 'Filename' routine is CASE SENSITIVE and in the case of the file 'Tutenchamun' it accepts only that combination of upper and lower-case and refuses any others ( such as. TUTENCHAMUN or tutenchamun )!

Notes by

The German author Mr. Frank Lauter / Germany has written this fine program (formarly for the company nibblesoft). He now works for the German company Some German words by him:

Hallo Zusammen!
Mal abgesehen davon, dass ich es echt putzig finde, dass es immer noch Leute gibt, die sich mit MZ-XXX auseinandersetzen, war ich doch etwas überrascht, das Ihr mein FL-DOS zum download auf Eurer Homepage habt...
Wusste garnicht, dass das so gut war, das nach 20 Jahren sich immer noch jemand dafür Interessiert...
Grüsse Frank Lauter (nibbelsoft)

FLDOS-800 version 1.x

Download FLDOS-800 1.x

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last updated June 1st, 2007
SUC / UK: Maurice Hawes