Read Only Memory Modules
Overview
The modules listed below are the available ROM modules. These include multifunction modules, equipped with ROM sockets.
| Memory Modules and Their Attributes | |||||||
|---|---|---|---|---|---|---|---|
| Module Number | M8012 | M7942 | M8021 | M8048 | M8578 | M8047 | M7195-FA |
| Model Number | BDV11 | MRV11-A | MRV11-B | MRV11-C | MRV11-D | MXV11-A | MXV11-BF |
| Introduced | 1977 | 1975 | 1977 | 1980 | 1982 | 1980 | 1983 |
| Discontinued | 1981 | ||||||
| Module Size | Quad | Dual | Dual | Dual | Dual | Dual | Dual |
| Q-bus Addressing | 16-bits | 16-bits | 16-bits | 18-bits | 22-bits | 18-bits | 22-bits |
| ROM Sockets | 24 | 32 | 8 | 16 | 16 | 2 | 2 |
| Socket Size | 24-Pin | 16-Pin | 24-Pin | 24-Pin | 28-Pin | 24-Pin | 28-Pin |
| Largest ROM | 2K x 8 | 512 x 4 | 1K x 8 | 4K x 8 | 32K x 8 | 2K x 8 | 8K x 8 |
| AC Bus Load | 2 | 1.8 | 2.8 | 2 | 3 | 2 | 2.3 |
| DC Bus Load | 1 | 1 | 1 | 1 | 0.5 | 2 | 0.5 |
| +5V Load | 1.6 A | 2.8 A | 0.6 A | 0.8 A | 1.6 A | 1.2 A | 3.5 A |
| +12V Load | 0.7 | 0.0 | 0.5 | N/A | N/A | 0.01 A | 0.06 A |
Summary
ROM modules are most useful for holding bootstrap routines. For this purpose, the MXV11-B2 bootstrap ROMs are preferred, due to their support of a wide range of devices. These ROMs come standard on the M7195-FA and can be installed on the M8578 module. Because these two modules also have 22-bit support, they tend to be the most desirable (and expensive) of the group. The M7195-FA also has the benefit of having RAM memory, two serial ports, a line time clock and line time clock register, which makes it more useful.
References
- PDP-11 Microcomputer Interfaces Handbook 1983-84 (EB-23144-18)
- Microcomputer Products Handbook, 1985 (EB-26078-41)
- LSI-11 Systems Service Manual, 3rd Edition, August 1981 (EK-LSIFS-SV-003)
Additional Resources
- MicroNote 3 - Compatible Bootstraps for the LSI-11/73
- MicroNote 5 - Q22 Compatible Options
- MicroNote 15 - Q-bus Hardware Bootstraps
