Re: Byte article - 64 bit Unix

Richard Henderson (
Sat, 26 Oct 1996 17:17:01 -0500 (CDT)

> I think we need to distinguish a few things about 64 bit OS's...
> Does the user address space have 64 bit addressability?

In theory Linux/Alpha could eventually give the user 62 bits of VM
address space. The current CPU implementations limit us to 43 bits.

> Do file offsets have 64 bit addressability?

Yes, off_t is 64 bits. None of the underlying filesystems currently
support files that big, but the VFS layer does not disallow it.

> Does the CPU do 64 bit arithmetic?
> Do memory move and copy routines use 64 bit at a time?

Of course.