ZX Format #01 31 октября 1995

IS-DOS     Программирование

IS-DOS - a beginner: IS-DOS - the first acquaintance

Category "IS-DOS - for beginners." No 1


              Eliseev VA

      "IS-DOS - the first acquaintance"

          (Journal version)

 (C) PENCRAFT 1995
 (C) IskraSoft 1995


            What is IS-DOS?


    In the traditional model of ZX Spectrum, not
having, as we know, disk drives, the role of
operating system to perform integrated
language interpreter BASIC. But now, finally, there was a 
Beta-disk interface, and many owners have Speccy opportunity to 
work with floppy disks. 


    There is no need to describe the benefits of working in a 
disk system, compared with tape, however, was soon seen by many 
that the disk operating System TR-DOS, sewn into the ROM 
Beta-disk interface, organizes the work with the disk is not 
the best way. Among the main weaknesses were noted, such as the 
inability to create files larger than 255 units, the inability 
to create the disk more than 128 files, no built-in shell for 
dialogue with the user, so you can not use the space freed by 
deleting files until until you run the command MOVE, this

it was just awful. In short, the time has come when the 
traditional TR-DOS ceased to meet the evolving needs of users, 
it is simply obsolete. There was an urgent need to creation of 
the new improved DOS, free from all the drawbacks of 
traditional. 


    This new alternative operating system for the ZX Spectrum 
was a system of IS-DOS, created in 1992 by the St. Petersburg 
company Iskra-Soft. When its design to use familiar

many users and a well-established ideology of MS-DOS,
used in computer firm IBM.


    Appearance of the internal membrane system was based on the 
image and likeness well-known IBM-shell-native

Norton Commander. Such continuity,
above all, allowed to bring your work at the ZX Spectrum to 
work on more powerful personal computers and

provide an easier transition from a home PC user to the 
professional. One of the main advantages of the new system was 
that it was loaded with floppy and did not require any hardware 
modifications in the scheme of the computer. This you can 
quickly jump to a new level without losing compatibility with 
the TR-DOS. 


    The new operating system is not immediately
found its way to the consumer. A small number of applications, 
the instability of earlier versions, the lack of advertisement 
and a rigorous system of protection against Copy a long time to 
contain the spread IS-DOS, however, recently the situation has 
changed dramatically. Appeared interesting applications, system 
has acquired a large number of utilities and external commands, 
joint efforts programmers and users had been taken from the 
vast majority of errors, and propagation conditions of the 
system have become more lenient. So now is the brainchild of 
the firm Iskra-Soft has successfully conquering the market and

tough competition for the system
TR-DOS.

    The purpose of this article - first of all, to help an 
inexperienced user to overcome the natural psychological 
barrier and acquire skills in the first operating system 
IS-DOS. However, information contained in this article

certainly be interested and experienced
users, long working environment
IS-DOS, since this system is still
poorly exposed in print, has some of the secrets and subtleties 
that often escape the attention and require special 
explanations. 


    This article describes the version
IS-DOS, released by Iskra-Soft in
May 1994, but much will be true for earlier versions. In those
cases where the work of different versions of the system will 
have fundamental differences, this will be specifically stated. 
At the same time in the text will be given the reference date 
of the establishment of a system, or version number. 


           So we start!


           Bootstrapping.


    One of the remarkable features
system IS-DOS, as has been said, is the ease of installing it 
on any Spectrum-compatible computer. To start working in the 
medium IS-DOS enough to insert a floppy disk with the system 
purchased must have a representative of the firm or an official 
distributor in the drive and run it. Prevention, by the way, is 
not accidental, since unauthorized copies of the system can 
indeed work is unstable, and also to present some very 
unpleasant surprises, but more on that later, but for now 
Recall that the bad work "pirated" copies of the company 
Iskra-Soft is not responsible carries.



    If you have a ZX Spectrum in 1948 with a floppy drive (not 
that uncommon even in our time), just press RESET, and the 
system starts, if Spectrum 128 or Scorpion - insert a floppy 
disk and exit in TR-DOS, but if you have a Spectrum PROFI 2 + -

first exit in TR-DOS 128, and then
insert a floppy disk or your computer
attempts to load a floppy IS-DOS as
CP / M'ovskuyu. By the way, never buy pirated cards and 
computers of dubious origin, I personally encountered instances 
in which IS-DOS in general it was impossible to run, although

machines in the author's performance system
worked fine.


    If you're in time for work already
are in the TR-DOS and contemplate on the screen saver 
Technology Research Ltd., or even if the cursor TR-DOS, this is 
the case even simple: to run IS-DOS is to type any command to 
access the disk, except that the command FORMAT, for example:

CAT, LIST, LOAD, RUN, and then ... however,
this deserves to be told separately.


           File wrapper.


    At the time of boot in the IS-DOS
computer memory is a lot of interesting events. So far we have 
enough know that the boot loader finds on

disk special file, which contains the body of the system and 
loads it into Senior RAM addresses. After that, control is 
transferred to the system already IS-DOS. The first thing that 
IS-DOS after the launch - it's located in the root directory of 
the boot disk file named autoexec.bat (well, just like the IBM 
PC) and performs a sequence of commands given in this file. 


    Autoexec.bat file is usually written
user and contains the commands to be executed always at the 
start system. It can be used, for example, to install the 
system configuration, the current date, resident programs, etc.



    Upon completion of mining autoexec.bat,
as well as in its absence, you get
the file wrapper IS-DOS. It provides the main mode of the 
system - work with files. 


    Externally, the file wrapper IS-DOS is
like Norton Commander - the same two
panel files, the line menu at the top of the screen, a 
rectangular cursor. Upon closer examination the similarity 
becomes even more complete. Generally, if you have ever run on 
IBM PC, then Throughout the session in the IS-DOS you

will not leave it feeling familiar.
If you've never seen Norton
Commander, do not worry - the file wrapper IS-DOS is so easy 
and friendly that you quickly learn and remember everything 
that you can come in handy future. In addition, if you have

subsequently run on IBM-compatible
car, work experience in IS-DOS certainly
You will facilitate its development and will give you a 
significant advantage in comparison with those who had not 
previously worked in the medium IS-DOS. 


    The top line - the menu system utilities. They are caused 
when you the corresponding number keys (1 to

9 and 0). When you click one of the above buttons, the 
corresponding system utility runs on the execution thus its 
name at the top stands a brighter color. 


        List of system utilities.

1 HELP - hint, operational assistance

2 USER - Call View

3 VIEW - Image File

4 EDIT - edit the file

5 COPY - copy files

6 RENAME - to rename a file, directory

7 crDIR - creating subdirectory

8 DELETE - delete files

9 MENU - menu block device

0 MASK - setting the mask to display files on the panel


    On the remaining screen space
there are two file panels - left and right. In this case one of 
them, in which the cursor is located, called the current, and 
another - an alternative. 


    The top row of each panel indicates the logical device name 
(in this case the drive), disk name or the currently displayed 
directory. The name of drive displayed in the case at

pane displays the contents of the main
- The root directory of the disk.


    The name of the disc consists of 8 characters and is 
separated from the logical device name colon. If the panel shows

one of the subdirectories, then after the colon
printed his name, and the number of points before it shows the 
level of nesting. 


    Let us explain by example. Let catalog
SHELL is a subdirectory of the root directory of device A with 
the name ISDOS, and the catalog is subdirectory HELP SHELL, 
then when displayed on the panel root in the top row will be 
printed: 


                 A: ISDOS


    If the panel display the contents of the directory A: 
SHELL, then the label will change to: 


                A:. \ SHELL


    If, however, enter the directory A: SHELL \ HELP,
will appear:


                A: .. \ HELP


    Number of points in this case shows that the HELP 
subdirectory is "Subdirectory of the subdirectory of the root 
folder of your drive, ie, the nesting level 2. A total of 
IS-DOS allowed 6 levels. 


    In fact, the system IS-DOS subdirectory
conveniently represented as a tree, for
It even has special programs
(Tree, treecat, treefile), but this -
later.


    Now consider in more detail the information located inside 
the windows panel. Each line of this window is three areas: 
area file name of the file name extension and service area.



    File name, as in TR-DOS, consists of
8 characters, but the requirements for the
characters are more stringent appropriate
standard of professional computers.
So in the file names in IS-DOS can not use the following 
characters: 


          ! @% '() \ {}

       <<>> []:? / *.,

as well as the character with decimal code 127


    Some of these characters have special meaning and will be 
considered later. The system IS-DOS may be used in file names 
with Cyrillic characters, which is very convenient for the 
Russian users.



    Extension (extent) the file name consists of three 
characters, and contains information about the type of the 
file. In the TR-DOS is roughly corresponds to the symbol file 
type. Name extension - a thing quite arbitrary, but there are 
some standard extensions (eg com, or res), used by the system, 
and also some of the traditional extension

to be followed when creating your own files (such as txt).


    In addition to these user
can create files with their own extensions, describing them in
configuration of the system but to avoid
confusion and ambiguity suggest adhere agreement.


    Thus, the main recommended file extensions for IS-DOS are 
as follows: 

com - executable file, the program

bat - batch text file

res - resident program

key - keyboard driver

typ - Display Driver

blk - disk device driver

lpr - printer driver

txt - text file

hlp - text file tips

wet - the working file text editor

as - text of the program in Assembler

obj - the object file

sys - system file

scr - screen file

cod - other files in the codes


    In addition, some applications
programs use their own specific
extension that allows you to easily distinguish
they have created the files from others.


    And finally, in the service area line panel is placed 
special information, more often - the length of the file in 
blocks, recall that the length of the block - the minimum 
element of the logical structure of the disc - in the IS-DOS is 
256 bytes, While the size of a disk sector in 1024

bytes.


    Now you need to do a little
retreat and to explain quite a substantial difference between 
the physical and logical structure of the disc. In the system 
of TR-DOS These two concepts are virtually identical, and

logical block size is the size of
physical sector. In professional
operating systems is not always so.
In particular, one track disk formatted in the IS-DOS consists 
of 5 sectors, volume of 1024 bytes each,

Consequently, each sector accommodates
a 4 block. Increasing the size of the block to
sector size leads to unnecessary consumption of disk space, 
since even the smallest file can not occupy less than 1 sector, 
and reducing the size of the sector to 256 bytes, while 
maintaining overall size of track 5 KB impossible due to a 
sharp increase in the service information - imagine 20 sectors 
per track! Therefore, it was chosen the best option turned out 
to be the most convenient in all respects. 


    Now, when the contents of your computer screen has finally 
ceased to impress the "Chinese letters" we can proceed with 
practical exercises. Working with the panels.



    The first thing to note is
that one of the lines in the panels differ
color from the rest. This - panel
cursor, you can move freely
panel with control keys.

Controlled cursor to the following keys:

Q or CS +7 - move up

A or CS +6 - going down

O or CS +5 - switch to the left panel

P or CS +8 - move to the right pane


    File panel consists of 19 lines.
If the actual number of files in more than 19, the display is 
shifted when the cursor of the window, opening the following 
file. 


    When switching to an alternative panel cursor position on 
the old panel preserved, ie about. when you return you will get 
it on the file from which you departed. 


    In order to enter into a subdirectory
you must install the cursor and
press ENTER. After that, the file panel will show the files in 
that subdirectory, and the top line, consisting of the points, 
which number corresponds to the the level of subdirectories 
used for return to the previous directory. If you

long wander in the wilds of the subdirectories and
You too lazy to get out again, you can use special keys for
quick return to the root

CS + O - yield to the root of the left panel

CS + P - Output to the root of the right
panel

CS + ENTER - the same in the current panel


    In addition, you can use shortcuts for quick
move inside the directory:

CS + Q, SS + Q - move to the top of the directory

CS + A - go to the end directory


    Well, if you suddenly want to have to
alternate panel was the same as that
at the current - at your disposal key:

SS + CS - duplicating the contents of the current
panel to the alternative with the transition
cursor on it


    If you need to read the directory, removable disks, or 
select another drive, use the keys: 

CS +1 - the device on the left panel

CS +2 - select a device in the right panel


    Pressing any of these keys will appear a special menu (see 
Figure) where you will be asked to choose

one of the currently available
devices.



      A B C D E F



    The system IS-DOS role of these devices
can play not only drives but also
other storage devices - hard
disk, virtual drive, organized in
RAM computer, etc. And all of them,
through the appropriate drivers, served from a user perspective
exactly the same. Therefore preferable to speak of logical 
devices, and not just the drives. 

    The device can be selected using
cursor keys (CS +5 or O - to the left
CS +8 or P - to the right), pressing ENTER fixes the choice and 
returns to the shell. If you for some reason changed their 
minds to change the device - press the SS + A or SPACE, and you 
back into the shell intact. 


    Starting programs produced by pressing ENTER. The cursor 
should be installed on the desired file name. Not

Remember that in the IS-DOS executable files have the extension 
com. However, This does not mean that when you press ENTER on

other files, nothing happens. The shell allows you to program 
the reaction by pressing the ENTER key for a file with

various extensions. To do this, there is a special text file
extent.txt, which contains a list
announced extensions and a description of the team, which is 
automatically called when press ENTER. The command is separated 
from the expansion of the colon. 


    The approximate contents of the standard
File extent.txt shown in Table. 1:

Table 1. Composition of the file extent.txt

The contents of extent.txt Reaction to ENTER

com: start com-file

bat: Q: SHELL \ exebat Larry

                      bat-files

scr: Q: SHELL \ exescr / w viewing screen

                      File

txt: Q: SHELL \ tv viewing text

                      File

hlp: Q: SHELL \ tv viewing text

                      File

wet: Q: EDIT \ edit edit

                      File

lpr: Q: RES \ set Driver Download

                      Printer

typ: Q: RES \ set Driver Download

                      Display

res: Q: RES \ set download Resident
                      term program

blk: Q: RES \ set Driver Download

bas: @ bas Larry

                      BASIC

mnu: Q: SHELL \ menu conclusion USER-menu

pac: Q: SHELL \ exepac unpacking code

                      block


    In addition to these you can ask any reaction to other 
extensions, such as for work in assembly language: 


           as: Q: ASSM \ as / auto


             obj: Q: ASSM \ link


    To start the editor font:


           fnt: Q: FONT \ f_e_unit


    To start advertising interpreter SHOW:


           shw: Q: SHOW \ exeshow


    For a graphical editor PICASSO:


        pic: Q: PICASSO \ picasso.com


    Of course, all caused by the program
must be present on the disk in a specified directory, otherwise 
you will get an error message No <filename>. 


    And finally, another operation that is available in the 
file shell IS-DOS - a marker files. The fact that some 
operations such as copying or deleting files, it is more 
convenient to carry out immediately with multiple files. For 
this you can Note these files to the panel by pressing

press SPACE.


    After pressing the SPACE bar to the name
marked file will change its color, and
the cursor will move one position in the same
direction in which he still dvigalcya
far. Thus, we can observe
neckolko files in a row, hitting only
at SPACE. When the end or the beginning of the directory 
pointer will change direction motion is reversed. 
Reconsideration pressing SPACE on the already marked file is 
unmark. 


    Evaluation of files saved in moving the cursor to the panel 
to the alternative panel, but at the entrance to a subdirectory 
and the output from a subdirectory all marks are cleared. 


    Also in the panels IS-DOS can not mention a sub-directory, 
or a group of subdirectories. If you need to make any operation 
on all files subdirectory - sign in and mark

all files. Several running forward, I can say that for such 
purposes can be use the utility mark.com, which

located in the directory UTIL \ and allows
noted a group of files at a specified mask.


    In conclusion, let me to summarize all the above 
information, more again lead the list of control keys

File panel:


      Basic control keys.

Q or CS +7 - move up

A or CS +6 - going down

O or CS +5 - switch to the left panel

P or CS +8 - move to the right pane

ENTER - the entrance to the subdirectory, run programs 
extent.txt 

CS + ENTER - exit in the root directory of the current panel

CS + O - yield to the root of the left panel

CS + P - Output to the root of the right
panel

CS + Q, SS + Q - move to the top of the directory

CS + A - go to the end directory

CS + SS - switching to an alternative panel
with duplication

CS +1 - the device on the left panel

CS +2 - select a device in the right panel

SPACE - mark file


         To be continued ...


   In the next issue we will contact you
talk about system tools IS-DOS, on the
the very ones whose names are written in
the top row of the main screen file
shell.