jeffz@sun.com (Jeffrey Zank - SBus Software) (05/30/90)
| >You need to be clear here. If you are using DVMA, 600 KBytes sounds about | >right for mb_ampalloc() and mb_mapfree() type of usage. Total space for | >DVMA is about 1 MByte, and its shared with all other devices that do DVMA. | >You really cannot "reconfigure" your kernel to add more space, you are | >limited by other kernel resources that currently are not configurable | >(PMEGS, and IOPB Memory for example). | | Please post a correction - DVMA is a softwared fiction on the SBus | machines - you can see all of the kernel context from the SBus. There | is no 1MB DVMA window in hardware on that machine. I have been asked to clarify this a bit more, so; I do not refer to DVMA as being a hardware limit here. I was attempting to point out that under 4.1 you can *expect* to map up about 600kbytes worth of DVMA (using mb_ampalloc()) and that the 1 MB is not configurable by the user (without hacking up the kernel). The 4/60 and 4/65 no longer have the hardware limits that forced the 1 MB limit. You should look at bp_mapin() for larger size mappings.