86ffe4bec2
PDP11/pdp11_rq.c re-uses ->filebuf as a sector buffer (under the #defined name rqxb) and allocates it as such. If an RQ disk is detached and another attached, this buffer would be lost and the pointer reset to NULL. sim_disk.c would only allocate the buffer if UNIT_BUFABLE is set, which means to buffer the whole disk. Since this rightly isn't set on RQ disks, the pointer would remain NULL and segfaults would ensue. See open-simh issue 274. add comment about safe re-use of filebuf
Open SIMH machine simulator
This is the codebase of SIMH, a framework and collection of computer system simulators.
SIMH was created by Bob Supnik, originally at Digital Equipment Corporation, and extended by contributions of many other people. It is now an open source project, licensed under an MIT open source license (see LICENSE.txt for the specific wording). The project gatekeepers are the members of the SIMH Steering Group. We welcome and encourage contributions from all. Contributions will be covered by the project license.
The Open SIMH code base was taken from a code base maintained by Mark Pizzolato as of 12 May 2022. From that point onward there is no connection between that source and the Open SIMH code base. A detailed listing of features as of that point may be found in SIMH-V4-status.
PLEASE NOTE
Do not contribute material taken from github.com/simh/simh unless you are the author of the material in question.