| Some notes for ftape users with PCI motherboards: | |
| ================================================= | |
| The problem: | |
| ------------ | |
| There have been some problem reports from people using PCI-bus based | |
| systems getting overrun errors. | |
| I wasn't able to reproduce these until I ran ftape on a Intel Plato | |
| (Premiere PCI II) motherboard with bios version 1.00.08AX1. | |
| It turned out that if GAT (Guaranteed Access Timing) is enabled (?) | |
| ftape gets a lot of overrun errors. | |
| The problem disappears when disabling GAT in the bios. | |
| Note that Intel removed this setting (permanently disabled) from the | |
| 1.00.10AX1 bios ! | |
| It looks like that if GAT is enabled there are often large periods | |
| (greater than 120 us !??) on the ISA bus that the DMA controller cannot | |
| service the floppy disk controller. | |
| I cannot imagine this being acceptable in a decent PCI implementation. | |
| Maybe this is a `feature' of the chipset. I can only speculate why | |
| Intel choose to remove the option from the latest Bios... | |
| The lesson of this all is that there may be other motherboard | |
| implementations having the same of similar problems. | |
| If you experience a lot of overrun errors during a backup to tape, | |
| see if there is some setting in the Bios that may influence the | |
| bus timing. | |
| I judge this a hardware problem and not a limitation of ftape ;-) | |
| My DOS backup software seems to be suffering from the same problems | |
| and even refuses to run at 1 Mbps ! | |
| Ftape will reduce the data-rate from 1 Mbps to 500 Kbps if the number | |
| of overrun errors on a track exceeds a threshold. | |
| Possible solutions: | |
| ------------------- | |
| Some of the problems were solved by upgrading the (flash) bios. | |
| Other suggest that it has to do with the FDC being on the PCI | |
| bus, but that is not the case with the Intel Premiere II boards. | |
| [If upgrading the bios doesn't solve the problem you could try | |
| a floppy disk controller on the isa-bus]. | |
| Here is a list of systems and recommended BIOS settings: | |
| Intel Premiere PCI (Revenge): | |
| Bios version 1.00.09.AF2 is reported to work. | |
| Intel Premiere PCI II (Plato): | |
| Bios version 1.00.10.AX1 and version 11 beta are ok. | |
| If using version 1.00.08.AX1, GAT must be disabled ! | |
| ASUS PCI/I-SP3G: | |
| Preferred settings: ISA-GAT-mode : disabled | |
| DMA-linebuffer-mode : standard | |
| ISA-masterbuffer-mode : standard | |
| DELL Dimension XPS P90 | |
| Bios version A2 is reported to be broken, while bios version A5 works. | |
| You can get a flash bios upgrade from http://www.dell.com | |
| To see if you're having the GAT problem, try making a backup | |
| under DOS. If it's very slow and often repositions you're | |
| probably having this problem. | |
| --//-- | |
| LocalWords: ftape PCI bios GAT ISA DMA chipset Mbps Kbps FDC isa AF ok ASUS | |
| LocalWords: SP linebuffer masterbuffer XPS http www com |