Long delays for USB realbtx boot
Bruce M Simpson
bms at incunabulum.net
Thu Sep 11 12:55:04 UTC 2008
I have hacked NanoBSD locally to deal with generation of images for
booting off USB keys. I am using the RELENG_7 branch as real-mode BTX
support is necessary to support USB boot.
During testing I noticed that whilst the images eventually boot, there
is an extremely long delay before doing so, between when the BIOS reads
the boot sector and when the BTX loader messages appear.
Test system Time
Thinkpad T43 1m 40s
ASUS Vintage AH-1 1m 7s
Any ideas why this long delay is occuring?
I see this with MBR geometries prepared for both USB-HDD (255H/63S/xxC)
and USB-ZIP (64H/32S/xxC) modes. I am not using the strict USB-ZIP mode
where everything resides on the 4th slice (da0s4) at the moment, as it
requires further NanoBSD patches.
I am not currently generating images sized to the entire USB key to save
space and time, so the cylinder size is smaller than the physical media,
this might also be a factor.
Thanks for any light you can shed on this.
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