GRC's Spectre and Meltdown testing software

On 26/01/2018 01:40, Paul wrote:
Brian Gregory wrote:


I only have a USB floppy drive and it doesn't seem to boot properly
from that.

I'll see if I can make a bootable CD out of it somehow.

My USB floppy seems to work OK. I can boot a memtest86+ floppy,
using my USB floppy drive, on any machine past 2005 or so.
It seemed somebody was coordinating the BIOS companies
behind the scenes, to make all of them provide support in
roughly the same year.

Only the USB 1.1 era machines will provide stiff opposition
to this. Once native USB2 (USB2 port on Southbridge)
showed up, things improved.

The BIOS has hard drive emulation of each device type.
A 250MB USB ZIP drive becomes a pretend 250MB hard drive.
A floppy drive over USB, becomes a 1.44MB hard drive.
I think the idea is, the caller uses INT 0x13 "read sector"
and the BIOS takes care of the details. If the device
type is not recognized, then the BIOS will refuse to
register it.

An example of "refusing to register", is PCI SATA cards
stuffed into year 2000 machines. The SATA card has a PROM
with INT 0x13 code in it (allowing booting on modern
machines). Even though the BIOS can see that blob, it
absolutely refuses to recognize the SATA card and
you can't even see it in the OS. The "P2B guy" reported
this some years ago.

Â*Â* Paul

It booted into the DOS on the floppy but crashed with a single beep from
the PC speaker when the DOS tried to load the program.

Probably some cockup in the BIOS.

--

Brian Gregory (in England).