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 program overlays average approximately 90 blocks each. On an unmodified disk drive, load times can be excessive, making the use of a disk speed enhancement system strongly recommended. JiffyDOS is highly recommended, though many other fastloader systems compatible with Color 64 may also be used. The Xetec Lt. Kernal hard drive with its Host Adapter is another supported option; when using Lt. Kernal, ensure the NMI trap is set to OFF (00) in the Lt. Kernal configuration. As a general guideline, if load times exceed 15 seconds, callers are likely to notice and may become dissatisfied.
An effective alternative to slow disk access is the addition of a Commodore 1764, 1750, or compatible RAM Expansion Unit (REU) expanded to at least 256K. These devices provide additional RAM, eliminating most overlay load delays during BBS operation. Color 64 supports up to 2MB of external RAM.
Dedicated boot programs are included to install RAMDOS and execute a BASIC script that copies required system files into REU memory. Even if you intend to operate primarily from an REU, it is advisable to first install and run the system using a standard disk device. Once you are familiar with system operation, transitioning to REU-based operation is straightforward.
You may notice that each program overlay filename begins with the “√” character. On a Commodore 64 or 128, this character is entered by holding either SHIFT key and pressing the @ key. The prefix is used to conceal system files from normal directory listings, preventing callers from viewing or downloading them.
Next Section: File Storage / Drives