Virtual Worlds #01 31 декабря 1999

Программирование

Technical assistance - Dos Review 4: The material on the format of the disk operating system from an unknown author.

  And finally, bring a letter, author unknown:

------------- Cut. ------------
"Hi All!


  I immediately developed a new format
store the files on disk,
and I want you to do it and look
evaluate all possible flaws. Maybe something to add or
remove the need, as in your opinion?


  The disc can be either
64 files or 64 directories for
16 files in each, for a total maximum of 1024 files on one 
disc. Can be spread fayldirektoriya, ie, no anything one, and 
all together. In established is the directory to create another

not, and can write 16 files. These restrictions are made for
facilitate the subsequent
in writing of any software
under this format, as well as for
reduce the occupied disk
space.


  Due to this format, we are losing another 9 tracks, ie first
track on the disk will 10.


  Now describe the format name
directories and files:

DIRECTORY:

+ # 00 - file mask:

       # 00 - end of catalog or

       directory;

       # 01 - deleted file or

       directory;

       # 02 - directory;

       # 03 - file dont delete;

       # 04 - hidden file or

       directory.

+ # 01 - # 14 - directory name of

             20 symbols;
+ # 15 - # 17 - type of three symbols;
+ # 18 - # 1A - create date

             DD-MM-YY;
+ # 1B - not used;!!!
+ # 1C - files in directory;
+ # 1D - directory lenght

             of sectors;
+ # 1E - first sector;
+ # 1F - first track.

FILES:

+ # 00 - file mask:

       # 00 - end of catalog

       or directory;

       # 01 - deleted file

       or directory;

       # 02 - directory;

       # 03 - file dont delete;

       # 04 - hidden file

       or directory.

+ # 01 - # 14 - file name

             of 20 symbols;
+ # 15 - # 17 - type of three symbols;

 + # 15 = 'B'-'BAS' for basic file

       'C'-'COM' for code file

       'D'-'DAT' for data file

+ # 18 - # 19 - start address file;
+ # 1A-# 1B - bytes lenght file;
+ # 1C - number directory

            for this file;
+ # 1D - lenght of sectors;
+ # 1E - first sector;
+ # 1F - first track.



  I mean, we now have 20 character name, 3 character type and a 
bunch of files on the disk. 


  As you look at it?


  Personally, I start writing tomorrow
initial software support, which is then
become one of the completions of new
DOS'a, and Phantom Ltd will write COMANDER under this format. "


Here is the answer to this letter:

"I would be in your place would have done
the following: 512 bytes per sector,
10 sectors per track, format
Disk MS-DOS. This immediately decides
question portability of files between all other dosami. In 
addition, there is no limit to the number of files on disk - 
limited only by the number of files / directories in the root

directory. Think about the users HDD - they again cut the screw
on slices of 640KB?


  Now about the format of the catalog. Take the original format
MS-DOS, and it shall contain the following correction: instead 
of file creation time record start address (this option

has been successfully applied to
BC). In addition, the MS-DOS in the records of the file is 
empty for another 10 bytes, so that you can turn around.



  IK? These restrictions are made
to facilitate the work in the future when

  IK? writing of any software under this format,


  Software should be written under the OSes, not "under the 
format." 

 IK? + # 15 = 'B'-'BAS' for

             basic file
 IK? 'C'-'COM' for

             code file
 IK? 'D'-'DAT' for

              data file


  Do you plan to use
new dosa as a replacement for TR-DOS?
If not, what about the BASIC can
soon forget.

 IK? + # 1E - first sector;
 IK? + # 1F - first track.


  Why repeat someone else's mistakes?
Linear arrangement of files
this is not true.


   __
__ / / Powered [pepsi inside]
\ _ \ / By MOTOROLA [smoking suxx]

------------- Cut. ------------
Nuts: I hope there are clear
without much comment, but it is certainly, to support these 
formats or not to support??



Time Keeper: I'd like to intrude
and say something, I remember it
letter - as it flew in the conference fido7.zx.spectrum, so
Now, even then, many cried
FU! And what ... many sudden
itch to reinvent the wheel?
It is not the only letter
similar content. And in general
TR-DOS replaced with something new already
not really! And if we talk about
HDD is IMHO is MS-DOS fits perfectly. Why??
Yes, because this screw
You can easily to PCs hem, and
rock, rock ... The problem with running the prog solved as 
follows: On HDD we have a bunch of files *. TRD, which

loaded into memory (RAM-DISK) when
availability thereof (there have to put a meg at least) and 
there (in the memory) can already do with them

anything. Bend naturally
should support the work of
drive on # 3D13. In general, it turns out that something like 
an emulator, but more on that another time ...


-------------------------------

  On this, I do conclude my
narrative. At various times I
had access to disks and
computers of different
systems, as well as emulators. AND
presented here, perhaps far
not that I know everything about formats
discs.


  I learned a lot by
emulator on the IBM PC. I must say, they can be used to study 
such systems, which are little who has seen live or theirs 
carriers do not contribute to their study on SPEKTRUM'e. For 
example, in computer COMMODORE 64 uses artful drive that is 
connected to special bus computer

six wires. Original and
Disc format: in lanes 1-17
offers 21 sector, 256
B, 18-24 - 19 sectors, 25-30
- 18, and the rest to 17, with tracks 36-40 - non-standard. 
Therefore, it uses virtual disks and files -

as a file format MS-DOS. The emulator simulates the work of real
drives, cartridges and cassettes
Using information from these
files. But it is possible
connect these drives
and cassettes with a printer
port. There are even special software shell that allows to 
combine standard and nonstandard devices under a common 
interface produce a convenient transfer

information between them. And still there and compatible 
drives, hard disk, and even converters to / from MS-DOS, but, 
as I understand, they are much more rare. 


  Therefore, only the standard
MS-DOS viewers can explore the virtual disks.


  Although, for example, computers MSX
use the disks very similar
on MS-DOS, and author of the OS
Both systems such as general, not
Despite the fact that such MSX'ya
called CP / M. Same virtual
drives are not always fully
a copy of the real and perhaps
I want to dig for real with the help of Spectrum.


  And the formats of cassettes and cartridges
generally not amenable to normal
Research. True who need
junk 1980-1984 period.


  I even caught a komputer - ATARI XE 130 was called.
Was with him and drive, and floppy
and even some of what the Russian-speaking
documentation. But the drive was
external, connecting cables
where something happened. Floppy read
with difficulty, but they also
used as two-sided. In short, I'm there for them
have not read, but nowhere directory
I found none. And the documentation here
just about him - not a word. In
general - if there is a specialist, then we continue on this
conversation. And the emulators are not.
And as long as such searches - was
because such a fact that I've already started writing about 
this very car, unfortunately faded. In general, time will tell. 

(Ed. ;-))) Chudo rulezzz! :-)


  And yet, I read a good description of the old company:
SPARK-224 is called. Some who
used to say that working with him. AND
would be worth about him, though
to the principle of the need
distribution utility (s)
information. Why, I do not even know whether connecting to it 
FDD 5'25 "and how he now

distributed to them to anyone
interested, at least from the
idle interest.


  The same, however, can and tell about all of the above
wheelbarrows. But I can say with certainty
say that someone kakimlibo way has access to them,
and on other similar machines do not
knows or does not want to know, despite the fact that the 
popularity of some of them even at the current moment can be 
very high in certain segments. And the availability of fresh 
programming provide for them, as well as detailed information 
about them and co-operation with the more powerful and

modern systems, will help
renew interest in them, especially
if the transition to the aforementioned
powerful system for any
reasons impossible.


  And the information can and should be
shares of all platforms, and
clustering them as time and help various descriptions
various standards and formats. Particularly important, in my 
opinion, tell us about PTs'shnye formats and

just to do it TIME KEEPER.
But the fact that such interesting things, often remain
neglected by those who have them
there, but their long searching for those who need them.


  I also have a lot of this
information, so the next
conversation might go about
graphic and audio formats.
In the meantime, you can write a disk
converter.


  And those who might say something
on the disc from above, as well as other
computers can write about it
me NUTS'u. I am pleased to
I will take all supplements, additions, amendments, corrections 
and criticism.



  As has been contributing to this
polzitelnoe thing I want to say thank you very much 
Unbeliever'u for its CD-R, which contained, In particular, 
different emulators soft and, consequently, the authors

This software, Ivan Roshchin - for
its formatter; Evdokimov Alex - for its program 'AFRODITA
3.0 ', and all those who helped
I format the drives in different
systems.



Crammed in the editor Dos Navigator

Date penultimate edition:

         29-07-99

         (C) Nuts, 1998-1999 years.

Date of last revision:

         9-03-2K

         (C) Org'n'Keeper ;-))))