Author
| Sunrise CompactFlash ATA-IDE question
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snout
msx legend
Posts: 4991 |  Posted: February 23 2003, 21:47 |
I'm afraid the Sunrise IDE BIOS can use a lot of optimization.
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sunrise
msx professional
Posts: 649 | Posted: February 23 2003, 21:57 |
Quote:
| I'm afraid the Sunrise IDE BIOS can use a lot of optimization.
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Perhaps it can, but Laurens makes a mistake the values he mentioned are valid on a PC with more than xx times the speed of a MSX and also based on USB figures.
I would like to have fair measurements, so donot compare our msx figures with that of a PC.
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Latok
msx master
Posts: 1727 | Posted: February 23 2003, 22:11 |
Hmmm, what a coincidence.........Tonight, I checked speed of my SCSI interface and the speed of the Sunrise IDE-interface on my MSX turboR. Both with the program HDSPEED. And the R800 was on while reading and writing....
There was a HUGE difference in speed. The Sunrise IDE interface is much slower than the Gouda SCSI interface. MUCH slower...
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Grauw
msx professional
Posts: 1005 | Posted: February 23 2003, 22:13 |
Sure, sure, but those PC figures I mentioned kinda indicate the speed of the Compact Flash carts itself, the max it can reach, because on the PC, the CF carts are the bottleneck. However from this data I conclude that on the MSX it would either be the CPU or the IDE interface its hardware because the CF still isn't anywhere near its limits... It's kinda confusing, when you're comparing a Z80A against a Z80H the IDE interface's speed doubles. That's quite a huge performance boost. However when comparing Z80H against R800 the speed increase isn't even close to that much, even though the R800 is more than twice as fast as the Z80H (or so I'm told). So this indicates something hardware limiting the performance.
Yet, on the other hand, there doesn't seem to be a tight hardware limit the R800 runs in to, because if that were so it should have been reached with a HD already, however the CF still creates a small performance boost on the R800 (about just as small as on the Z80H). So this would indicate that it's perhaps not fully operating in R800 mode but switching between Z80A and R800 mode on a 50/50 basis, which would explain the speed similar to the Z80H.
It could ofcourse also be a combination of both hard- and software. Anyways I'm not saying the Sunrise IDE is bad or anything  just wondering whether the R800 support perhaps can be improved a little... maybe.
~Grauw |
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snout
msx legend
Posts: 4991 | Posted: February 23 2003, 22:33 |
Usually, the turboR switches back to Z80 mode during disk operations. There is a patch for this however (R800-DR.BAS) which increases the speed of IDE operations. I asked Jon once why this patch wasn't incorporated in the BIOS, but according to him the IDE BIOS was not meant for this (it's got 512K flash, where could we use it for instead?? Good FDE emulation like MegaSCSI has!  )
I'd really like a highly (turboR) optimized IDE interface, I think speeds higher than 280K/s can be reached. |
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GuyveR800
msx guru
Posts: 3048 | Posted: February 24 2003, 02:06 |
If I'm not mistaken, MegaSCSI can get up to 700kB/s in R800 mode.
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dhau
msx master
Posts: 1056 | Posted: May 15 2003, 23:02 |
Where can one buy MegaSCSI?
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snout
msx legend
Posts: 4991 | Posted: May 16 2003, 13:57 |
dhau - I think more people will read your question if you start a new topic about this in the trading section.
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POISONIC
msx professional
Posts: 883 | Posted: May 18 2004, 23:46 |
In a test with a fucked up R800 @40Mhz And a NOVAXIS SCSI interface the speed is about 1Megabyte per sec from a 2Gigabyte quantum fireball SCSI HD
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dhau
msx master
Posts: 1056 | Posted: May 18 2004, 23:53 |
How did you f*cked it up? I want to f*ck up my GT the same way
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snout
msx legend
Posts: 4991 | Posted: May 18 2004, 23:59 |
You can 'just' replace the crystal of the R800 so it will run ~40MHz (well, if you define the regular speed of the R800 ~28MHz). However, the VDP doesn't really handle that speed, which is why I don't recommend this upgrade |
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Sonic_aka_T
msx guru
Posts: 2268 | Posted: May 19 2004, 02:11 |
Quote:
| You can 'just' replace the crystal of the R800 so it will run ~40MHz (well, if you define the regular speed of the R800 ~28MHz). However, the VDP doesn't really handle that speed, which is why I don't recommend this upgrade
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I'll run just fine if you dump the whole lot in your freezer...  Ofcourse you'd have to dump your monitor in there as well, so you may want to make a little window in your freezer and buy yourself a wireless keyboard |
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GuyveR800
msx guru
Posts: 3048 | Posted: May 19 2004, 02:33 |
it will not run fine no matter how much you cool it. It's not the CPU that's the problem.
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dhau
msx master
Posts: 1056 | Posted: May 19 2004, 02:37 |
So what is the maximum "safe" overclock via quartz?
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dhau
msx master
Posts: 1056 | Posted: May 19 2004, 02:39 |
Quote:
| dhau - I think more people will read your question if you start a new topic about this in the trading section.
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Hey, no problem Since I asked this question, I decided to build it myself
More fun this way. I like the smell of fried fingers (my soldering iron is total suxxor from Radio Shack, I need to buy a good one from Solomon) |
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