Overlays
Introduction - The Program Overlays
To get the most out of the Commodore 64's limited amount of memory, the BBS program has been divided into several program overlays. All the overlay file names begin with "√bbs." and have a suffix in the form of an alphanumeric. For example:
- √bbs.ovl 8000 = Main Overlay, Version 8.0
- √bbs.ovl 8001 = Main Overlay, Version 8.0 revision 1
- √bbs.ovl 8100 = Main Overlay, Version 8.1
- √bbs.ovl 810a = Main Overlay, Version 8.1.0a
For the purposes of this manual, suffixes will not be referred to when discussing specific overlays, but note that version 8.1.0a does have some unchanged files from previous iterations of 8.0/8.1, so not all files will be shown with suffix “810a”.
| Overlay | General Description |
|---|---|
| √bbs.init | Responsible for initial variable setup, caller logon, and password maintenance. |
| √bbs.msgs | Responsible for all public and private messages, composing and reading. |
| √bbs.xfer | Responsible for single and multi-file uploads/downloads, and directory maintenance. |
| √bbs.ovl | Responsible for multi-uploads, help and text files. |
| √bbs.ov2 | This handles loading your online games and modules. Use of the module loader in "√bbs.ov2" is optional to the Sysop. Version 8.1.0a now includes an alternate games module, √bbs.games. |
| √bbs.ov3 | This is used for a system guestbook / “wall” and should be included as part of your system. |
| √bbs.term | A full-featured terminal program. Optional for install. |
| √bbs.games | A new game module as an alternative to √bbs.ov2. This module is set to use the AUX3 designated drive and the √bbs.games file itself should be resident there. It is the only overlay placed outside of the designated “programs” drive. |
| √bbs.profile | User Profile customization area, permits users to create a customized signature for messages as well as a greeting banner to display to other users when they are messaging that person. |
If you are going to use Network, then there are two other overlays that Color 64 will use.
| Overlay | General Description |
|---|---|
| √bbs.nw1 | This contains the Network message editor, and handles calling and receiving calls. |
| √bbs.nw2 | This handles the Network maintenance and the distribution of messages. If you do not wish to run Network, then these files are not required. |
| Note: File prscrn52750 is also required as part of this. |
Disk Speed Enhancers
The average size of these overlays is about 90 blocks each and would require a long time to load on an unmodified disk drive, so it is required that you use a speed enhancer. JiffyDos is highly recommended, although there are many other types of fastloader systems that are compatible with Color 64. You can also use the Xetec Lt. Kernal hard drive with its own Host Adapter (make sure you set the NMI trap off - 00 - in the Lt. Kernal setup). If any load time takes more than 15 seconds, you will probably get complaints from your callers.
Another solution to the slow disk access is to add a C1764, C1750, or compatible Ram Expansion Unit (REU) expanded to at least 256K. These units add 256K or 512K (or more if expanded) of internal RAM to your 64, eliminating program loading delays in the BBS. Color 64 will support up to 2 megabytes of external RAM. Separate boot programs are used that will install RAMDOS and then load a BASIC "script" which will copy all the necessary files onto your REU. Even if you plan to use REU for your system, I suggest that you first install it without the REU and run it off a disk device. Then once you are comfortable with the operation of Color 64, you can easily switch to REU use.
As you may have noticed, each of the program overlay filenames begins with a “√“. To type this character on Commodore 64 & 128, you must press and hold either shift key, then press the @ key. This special character is used to hide all the system files from being seen or downloaded by your callers.
Next Section: File Storage / Drives