Chapter I: General Information
There are
several things which are often used and would fit the description of
general information. The items covered in this chapter are used in
almost every module you can find.
The Function
Keys
IMAGE
BBS uses function keys to represent specific ASCII characters which:
-
allows typing special characters in
quote mode rather than using CHR$() codes, and
-
avoids the pitfall of truncating lines, or the necessity of
using custom I/O routines to read SEQuential data files.
F1: Comma (,)
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F5: Quotation mark (")
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F2: Question mark (?)
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F6: RETURN [CHR$(13)]
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F3: Colon (:)
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F7: Asterisk (*)
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F4: Equal sign (=)
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F8: Up-arrow (^)
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The
Drive Designators:
IMAGE BBS uses six drive [designators to] identify the system drive in
which to find a specific file. The active drive is set by setting the
variable DR to a value of 1 through 6 as I will describe below:
1: System drive. This drive should contain all of your s.*
files. When writing your own modules, all files which are usually read
but NOT changed often (like intro screens) should carry the s.
prefix and be stored on this device.
2: E-mail
drive. This drive contains all mail (m.*), forced
mail (fm.*), and network (nm.*)
files.
3: Etcetera drive. This is one of the most
active drives on your system. It contains all files which change often,
and should be used to store data which needs to change frequently.
[Note: these files have an e.* prefix.]
4:
Directory drive. This drive holds all the sub-directories (d.* files)
used by the system.
5: Plus-file drive.
This drive holds all IMAGE BBS program modules.
6:
User drive. This drive is used to store the user records and
alphabetical user list.
Time and Date Format
IMAGE BBS
uses an 11-digit string to represent the current time and date. This
information is stored in D1$.
1 90 11 03 80 45 IMAGE BBS will translate this into the string
^ ^ ^ ^ ^ ^ "Sun, Nov 3 1990 12:45 PM"
| | | | | |
| | | | | +---- Minutes 00-59
| | | | |
| | | | +------- Hour 00-11: AM
| | | | 80-91: PM (subtract 80 to get correct hour)
| | | |
| | | +---------- Date 01-31
| | |
| | +------------- Month 01-12
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| +---------------- Year 00-99 (plus hard-coded century base)
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+------------------- Day 1-7 (1=Sunday, 7=Saturday)
[Note: Spaces and diagram added for clarity. Also, one thing
the manual doesn't mention is putting CHR$(4),
CTRL-D, in an & statement followed by a
properly formatted 11-digit string will display a readable time/date
stamp. To wit,
&"[CTRL-D]19011038045"
will echo the same string as at the top of this explanation.]
Carrier Loss
All prompts for user input must be protected against a lost
carrier! This is simple, and easily forgotten. If the carrier is lost,
the system will automatically drop the user's time to zero. Time
remaining is stored in the integer variable TR%.
The simplest way to protect your system is to check the value of
TR%: if it is less than one either GOTO
line 1811, or RETURN if it
is a subroutine.
Access Levels
IMAGE
BBS uses the following table to determine which access groups (0-9) have
access to seperate areas of the system.
Group
|
Value
|
|
Group
|
Value
|
0
|
1
|
5
|
32
|
1
|
2
|
6
|
64
|
2
|
4
|
7
|
128
|
3
|
8
|
8
|
256
|
4
|
16
|
9
|
512
|
To figure out which access levels would have
access to certain areas, you must add the values of the access groups
you wish included together. For example, if you wanted all groups
allowed access to the function, you would need an access code of 1023.
If you just wanted levels 8 and 9, the access code would be 768
(256+512). [Note: Most prompts that ask for access levels will let you
type a question mark and RETURN, and the system
will figure out the correct numerical value for you.]
Plus Files
A plus file is a BASIC module which is loaded into memory when needed
by the BBS. The maximum size that any one plus file is 56 CBM blocks.
There are two distinct types of plus files: the standard plus file, and
the mini plus file.
The standard plus file can
range from lines 1 to 999.
-
Under no circumstances should you allow your program to fall through
past line 999.
-
The last
line of the program should be a REMark.
-
Depending on the type of module, it should return control to
the main system via a GOTO 1811 or a RETURN.
The mini plus file is a smaller module which may be loaded
between the plus file and the main BASIC program. Care should be taken
when using these types of modules. I will cover more on these modules
further on in this chapter.
ML Modules (++ files)
An ML
module is normally used for such items as transfer protocols and
copiers. However, they can be used for any function that you wish. All
ML modules must reside in the $C000 to $CA00
range of memory.
Mini Plus Files
A mini
plus file is a module or series of modules which link to a plus file
module in much the same way a plus file links to the main module. When
using mini modules, the size of the plus file is limited to 40 CBM
blocks instead of 56. Also, the mini module may range from one line
higher than the main module (the first line must be a REMark) to line
999.
A standard module using mini plus files will
look like this:
1 - 798 Main BASIC module
799 REMark
800 REMark (first line of mini plus module)
801 - 998 BASIC mini module
999 REMark
1000 - IM module
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