[HN Gopher] Why doesn't Windows use 64-bit virtual address space...
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Why doesn't Windows use 64-bit virtual address space below
0x00000000`7ffe0000?
Author : signa11
Score : 83 points
Date : 2022-12-18 06:28 UTC (16 hours ago)
(HTM) web link (devblogs.microsoft.com)
(TXT) w3m dump (devblogs.microsoft.com)
| darknavi wrote:
| I enjoy the short and sweet blog posts from Raymond Chen on "Why
| does Windows X?".
| krylon wrote:
| He is great at summing up these things in a way I can
| understand (most of the time, not being very experienced with
| Windows internals) without having the feeling he is dumbing it
| down, just that he is explaining it very clearly.
| [deleted]
| 082349872349872 wrote:
| tl;dr several reasons, the most specific of which is "to keep
| linker relocs simple"
| alexklarjr wrote:
| ...on a long dead architecture.
| ourmandave wrote:
| Chen is the poster boy for backwards compat.
|
| They used to work very hard to make sure updates didn't break
| popular programs that used undocumented hacks.
| AnimalMuppet wrote:
| > They used to work very hard to make sure updates didn't
| break popular programs that used undocumented hacks.
|
| Obsessively.
|
| I worked for a company that sold a security auditing tool.
| We cared very much about which version of Windows we were
| running on. When Microsoft came out with the next version
| of Windows and to our dismay, we found out that our
| software recognized it as the old version.
|
| Turns out that Microsoft had found (pre release) that the
| new version broke our software. It reported "unknown
| version" or something. So they added us to a long list of
| applications that, when those applications asked for what
| version of Windows they were running on, Windows lied and
| told them an earlier version.
|
| It cost us some heartburn to work around Windows trying to
| be helpful to us...
| jasoneckert wrote:
| I still have Windows 2000 installed on a Digital Ultimate
| Workstation (2x Alpha 21164). I turn it on every few years
| when I need a nostalgia kick ;-)
| KMag wrote:
| So sad to see Alpha die off, especially since I haven't
| noticed any architectures with anything like PALCode spring
| up since. The Alpha's firmware was essentially a hypervisor
| that only supported a single guest, and the OS kernel had
| to upcall to the firmware for any privileged operations.
|
| In particular, it would be nice to have userspace programs
| be able to take advantage of new/larger registers without
| requiring the OS kernel to support the extra CPU state. If
| the firmware (which presumably is available as soon as the
| new CPU ships) handles the context switch, then the OS
| kernel doesn't need an update.
| analog31 wrote:
| They need to reserve the first 2147352576 bytes for the Color
| Graphics Adapter display buffer.
| herpderperator wrote:
| What does the ` mean?
| muststopmyths wrote:
| That's the convention on windows for denoting 64-bit addresses,
| separating the two 32bit parts with the backtick. Don't recall
| why now.
| avianlyric wrote:
| I assume it just makes the address easier to read. I imagine
| most programs don't deal with address spaces larger than 4GB,
| so being able to quickly identify the lower bytes of the
| address when physically looking at a memory address is
| probably quite handy.
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(page generated 2022-12-18 23:00 UTC)