torq@tardis.computer-science.edinburgh.ac.uk (06/25/91)
On the Acorn SCSI card that I have, there is a facility to do background transfer, by setting b29 of r1 and a address to call in r6 on entry to SCSI_op. Is this facility unique to the acorn card? is it used in riscix? Which cards are actually compatible with the riscix device drivers? Since acorn have released riscix to ordinary archimedes owners it might be of some benefit to know this.. Andy
kwelton@acorn.co.uk (Kevin Welton) (06/27/91)
torq@tardis.computer-science.edinburgh.ac.uk writes: >On the Acorn SCSI card that I have, there is a facility to do background >transfer, by setting b29 of r1 and a address to call in r6 on entry to >SCSI_op. Is this facility unique to the acorn card? is it used in riscix? The facility is nothing to do with Acorn's SCSI card, it is a feature provided by RISC OS. Under RISCiX, the kernel blocks all read/write operations until the transfer is complete, but there is nothing stopping you forking off another process to do the transfer for you. >Which cards are actually compatible with the riscix device drivers? Since >acorn have released riscix to ordinary archimedes owners it might be of some >benefit to know this.. The RISCiX device drivers work with Acorn's SCSI card only. >Andy Kevin -- Kevin Welton Email: kwelton@acorn.co.uk Acorn Computers Ltd Phone: (+44) 223 245200 Cambridge, UK Fax: (+44) 223 210685
banksie@rata.vuw.ac.nz (Philip Banks) (06/28/91)
In article <9106251106.AA05878@ucbvax.Berkeley.EDU> torq@tardis.computer-science.edinburgh.ac.uk writes: >On the Acorn SCSI card that I have, there is a facility to do background >transfer, by setting b29 of r1 and a address to call in r6 on entry to >SCSI_op. Is this facility unique to the acorn card? is it used in riscix? The facility is not unique to the card but rather has been included in the filing system mangemant routines by Acorn. A filing system can set bit 29 of its descriptor word to indicate that it is capable of background transfers. I beleive that this is for the `non exsistant' Risc OS 2.5 which will be released sometime in the near future as it is rumoured (by the Micro User I think) to have fully backgrounded file access.(Among other things) Of course all the PD filing systems will still be non backgrounded.... On another vein this desire for Virtual memory that people have been expressing. To be honest I don't think the Arc really needs it. I upgraded to four Megs (I own an A3000 with floppy. Unfortunately sans hard drive...<sigh>) and even with an 800K ram drive and somewhat ridiculous loading of applications I find it very hard to push the machine below the 1 Meg mark. With the new machines coming that have 16 Meg I really do not think that memory will be a problem. We have been somewhat fortunate to have an Operating system in which the `small is beautiful' principle can be achieved (and nearly always without a loss in functionality). When you compare the functionality and size of an application like Impression with the nearest Mac & IBM equivalents this becomes very clear. If you really want an improvement worth the time how about we finally get an Arc that has :- -inbuilt 24 bit colour Video with *its own private Video bus*! This is *the* thing that I think causes the Arc to suffer. Always having the full 4.7 odd MIPS available to you no matter what screen mode would so much more useful than virtual memory. -An ARM 3 unit for the A3000. This one really niggles me as it is the only current way around the Video DMA problem mentioned above. And it is not available for the A3000! Now I *know* that VLSI have made ceramic versions of the ARM3 that are perfect for fitting in the A3000 but that they are apparently held up in talking to acorn about warranty problems etc (due to the soldering...). Now the main reason I bought the A3000 rather than ,say, a 310 was because:- 1) It was cheaper. 2) It was fully compatible with the hardware then available. 3) It had the nice easy memory upgrade option built in. So with this great hardware compatibility I still cannot get an ARM3 for my machine! And being a speed fiend ,not to mention I have a few simulations that need the crunch, I find this lack very irksome. So how about we get these sort of improvements instead? Philip -- *------------------------------------------------------------------* @@@@@@/| | BANKSie! (aka Philip Banks) BANKSIE@rata.vuw.ac.nz | @@@@@/#| | An Arc owner stuck in an almost non Arc spot. | @@@@/##| |Thus Quoth the Raven `Nevermore!'.And my spirits sank to the floor| @@@/---|
kers@hplb.hpl.hp.com (Chris Dollin) (06/28/91)
Philip Banks says:
On another vein this desire for Virtual memory that people have been
expressing. To be honest I don't think the Arc really needs it. I
upgraded to four Megs (I own an A3000 with floppy. Unfortunately sans
hard drive...<sigh>) and even with an 800K ram drive and somewhat
ridiculous loading of applications I find it very hard to push the
machine below the 1 Meg mark. With the new machines coming that have
16 Meg I really do not think that memory will be a problem.
I now need a 2+Mb wimpslot to C-compile one of the modules of my virtual
machine interpreter. They day before yesterday, my wife had installed [*1]
Poster, Impression, and a couple of other applications. Result: I couldn't
rebuild the VM.
Yes, I'd like virtual memory (especially as my current garbage collector is a
stop-and-copy one). We won't be able to afford more store for a while yet ...
[*1] On the icon bar, and I didn't want to abandon her work.
--
Regards, Chris ``GC's should take less than 0.1 second'' Dollin.torq@tardis.computer-science.edinburgh.ac.uk (06/29/91)
In article <1991Jun27.212244.5025@rata.vuw.ac.nz> banksie@rata.vuw.ac.nz (Philip Banks) writes: > > -inbuilt 24 bit colour Video with *its own private Video bus*! > > This is *the* thing that I think causes the Arc to suffer. Always > having the full 4.7 odd MIPS available to you no matter what screen > mode would so much more useful than virtual memory. A friend of mine who designs hardare addons for the arc is doing a little project with two-port RAM, so that hopefully he can get a private video bus in the arc.. (i dont know the details - trade secrets!!) sounds like one to watch out for... Andy