If I try to open a block device using open(my $fh, "+<", "/dev/foo") the device node is truncated and replaced with a regular file. I'm guessing the solution involves sysopen() and O_DIRECT but I'd rather not experiment too much with these things and I can't seem to find any good docs on it. Can someone point me to example code showing how to "safely" do random read/write ops on a raw block device?

Also, I know syswrite() and seek() are mutually incompatible. Does the 4th parameter to syswrite() do the same as seek() on the file handle?

Edit:

"When it comes to opening devices, it can be easy and it can be tricky. We’ll assume that if you’re opening up a block device, you know what you’re doing. The character devices are more interesting."
In all of Perl's documentation, this must be the single least useful bit of info :-|
-- Time flies when you don't know what you're doing

In reply to Random read/write on a block device by FloydATC

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