max drive size over USB port

  • Thread starter Thread starter needtoknow
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needtoknow

I have an older computer with a promise controller card in a PCI slot
that supports a max drive size of 120gb.

If I connect a external hd over a USB2 port, what is the max size of HD
recognized.

The primary onboard IDE is enabled (BIOS) for the floppy, is this where
the computer gets what it needs to see the drive ??

I am running XP pro service pack 2.


thanks
 
I have an older computer with a promise controller card in a PCI slot
that supports a max drive size of 120gb.

If I connect a external hd over a USB2 port, what is the max size of HD
recognized.

The primary onboard IDE is enabled (BIOS) for the floppy, is this where
the computer gets what it needs to see the drive ??

I am running XP pro service pack 2.
Click to expand...

The drive size limitation is in the BIOS (both IDE cards and on
mainboard) so if you buy an external drive, it should be fine on USB.
If you buy an external enclosure for an internal hard drive, do make
sure the enclosure does support large hard drives.
 
needtoknow said:
I have an older computer with a promise controller card in a PCI slot that supports a max drive
size of 120gb.
Click to expand...

The bios on that card may well be upgradeable.
If I connect a external hd over a USB2 port, what is the max size of HD recognized.
Click to expand...

There is no practical maximum with a drive connected like that.
The primary onboard IDE is enabled (BIOS) for the floppy,
Click to expand...

What has the floppy got to do with anything ?
is this where the computer gets what it needs to see the drive ??
Click to expand...

The bios is just one aspect of that 127GB limit.
 
Previously needtoknow said:
I have an older computer with a promise controller card in a PCI slot
that supports a max drive size of 120gb.
Click to expand...
If I connect a external hd over a USB2 port, what is the max size of HD
recognized.
Click to expand...
The primary onboard IDE is enabled (BIOS) for the floppy, is this where
the computer gets what it needs to see the drive ??
Click to expand...
I am running XP pro service pack 2.
Click to expand...

USB uses teh SCSI "storage" class command set. This has at least
32 bit sector numbers (64 bit is avauilable as extension).

This gives you

2^32 * 512 Byte = 2TB. XP should support that as well, so
no problem for the time being. For the future, I would
expect that the 64 bit secor numbers need to map to 48 bit
LBA sector numbers. That would then be 64PB.

Arno
 
2TB, just like SCSI II.
Click to expand...

Not true. USB itself do not have the information on drive size. The
drive size is the fuction of USB <-> IDE or USB <-> SCSI interface.
 
Not true. USB itself do not have the information on drive size. The
drive size is the fuction of USB <-> IDE or USB <-> SCSI interface.
Click to expand...

Huh? The USB storage class explicietely uses the SCSI II command set
and parameters, and hence has exactly the same limitations.

Arno
 
Not true. USB itself do not have the information on drive size. The
drive size is the fuction of USB <-> IDE or USB <-> SCSI interface.
Click to expand...

Whatever that's supposed to mean.
 
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