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Bypass 8gb scsi limit possible (for DOS)?

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First post, by Marco

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Hello all,

For Standard Isa controllers as the advansys ABP 5142 or similar Adaptecs SCSI2 there is the famous 8gb limit. I understood so far that win95c or higher can read larger partitions bypassing 8gb when running.

Question:

- is this valid for the GUI only or also msdos 7.1ff?
- is there any known way to bypass this limit independent from (dos) versions? Thinking about special ASPI driver or special SCSI overlay software (as EZdisk for IDE)?

Thanks

1) VLSI SCAMP 311 | 386SX25@TI486SXLC2-50@63 | 16MB | CL-GD5428 | CT2830| SCC-1 | MT32 | WDC160GB/7200/8MB | Fast-SCSI AHA 1542CF + BlueSCSI v2/15k U320
2) SIS486 | 486DX/2 66(@80) | 32MB | TGUI9440 | LAPC-I

Reply 1 of 6, by ElectroSoldier

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Can the controller youre using see disks larger than 8Gb with its current fireware and BIOS?

Reply 2 of 6, by Marco

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Thanks I will check this

Why don’t I know yet: because I plan to get a scsi to ide converter to use my lastgen pata drive

1) VLSI SCAMP 311 | 386SX25@TI486SXLC2-50@63 | 16MB | CL-GD5428 | CT2830| SCC-1 | MT32 | WDC160GB/7200/8MB | Fast-SCSI AHA 1542CF + BlueSCSI v2/15k U320
2) SIS486 | 486DX/2 66(@80) | 32MB | TGUI9440 | LAPC-I

Reply 3 of 6, by Jo22

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Hi, maybe it's because of the limits of the int13h handler provided by the SCSI BIOS?
Because I think SCSI itself doesn't use CHS. It's more like LBA from the very start.
Using MS-DOS 7.1 might help, too. It is "LBA aware" and doesn't have an 8 GB limit anymore.
Maybe it supports extended int13h, too, not sure.
FAT32 partitions on DOS can be up to 2 TB in size, in theory.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

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Reply 4 of 6, by Disruptor

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For some controllers my pal mkarcher has developed a BIOS and/or driver patch:

mkarcher has added INT13E support for Adaptec's VLB and EISA controllers:
Showing some love for Adaptec's ugly ducklings: Adding big drive support to EISA and VL controllers
He also has added INT13E support for NCR/LSI/Symbios 810 SDMS BIOS:
INT13 Extensions to SDMS 3.0 & 4.0 - SCSI by NCR / Symbios Logic / LSI Logic

With INT13E support you can use up to 2 TB. I've tested it with an SCSI-to-IDE in combination with an IDE-to-SATA adapter.

So my 486 DX 50 with EISA 2740W is whopping out 18 MB/s of a 2 TB SATA disk. But I think my 18 GB 7200 RPM drive is matching more to this machine.

Reply 5 of 6, by Marco

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Yes nice really great work. Already found these updates. Unfortunately not for advansys scsi controller. Anyway it seems as if I just have to try it out 😀

1) VLSI SCAMP 311 | 386SX25@TI486SXLC2-50@63 | 16MB | CL-GD5428 | CT2830| SCC-1 | MT32 | WDC160GB/7200/8MB | Fast-SCSI AHA 1542CF + BlueSCSI v2/15k U320
2) SIS486 | 486DX/2 66(@80) | 32MB | TGUI9440 | LAPC-I

Reply 6 of 6, by Disruptor

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1542C should have support for INT13E too.

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