[CentOS-devel] CentOS 7 (1503) i686 Beta Architecture

Sat Jun 6 16:05:45 UTC 2015
Lamar Owen <lowen at pari.edu>

On 06/06/2015 03:38 AM, Toni Spets wrote:
> If you think it this way, why bother with the i686 build at all? Your 
> dual core 2010 vintage Intel Atom D510 can run 64-bit CentOS 7 anyway. 
> This is why dropping SSE2 requirement would be benefitical as it would 
> allow running it with a larger amount of x86 CPUs that can't run the 
> 64-bit variation at all.
>

Older Xeon systems that are non-64bit capable are one set of possible 
targets.  If PAE is disabled, Pentium M is likewise a good target (we're 
running Windows 7 Pro here on some Dell Latitude D610's with reasonable 
performance; CentOS would run on these quite well, as they are 
single-core 2GHz Pentium M with 2GB of RAM and somewhat reasonable ATI 
X300 video, if PAE isn't required).  Of course, NetBurst Xeon is a 
performance pig, but a non-profit that has an older but high-quality 
server with NetBurst Xeon in it might not have the discretionary funds 
to obtain a similar quality system with a more modern and 
power-efficient CPU; they'll run it until it breaks and it's no longer 
discretionary to replace it.

Pentium M on the other hand performs very well at 2GHz.  We have a 
number of D600's, but they are just not quite up to the task of running 
Win7 reasonably well.  That era, 2004 or so, seems to be the break-point 
for boxes that are still very usable running modern workloads.  D600's 
still make excellent service laptops for things requiring serial ports 
(like our datum SSU-2000 timeserver with a PRS45A cesium primary 
refclock).  I have a couple of D600's parked at a co-lo just for that 
sort of troubleshooting purpose where RS-232 is still needed, and 
another D600 running the software for our Advin Pilot EPROM programmer, 
which needs a parallel port connection (I did mention specialty hardware 
before.....).

> Surveying CentOS 6 users who run the i686 version on non-SSE2 CPUs 
> would also give some sort of indication how many potential users are 
> going to be left out and would need to change their enterprise grade 
> distribution to something else when EOL hits.

I'm still running a 32-bit CentOS 5 install due to some proprietary 
software that is not available yet in a 64-bit form.  Keeping up to date 
with security fixes while running this software will become increasingly 
difficult, but when a hardware vendor doesn't or didn't provide 64-bit 
driver modules what exactly are you supposed to do for specialized 
hardware that is expected to be in production for 15 years?  (Yes, 15 
years, per the grant proposal language.....)

>
> My specific use case isn't really worth CentOS 7. I don't think I 
> would ever *really* run anything useful on a 12 year old laptop, it 
> was just the only x86 system I still have around. The CPU generation 
> itself, however, isn't completely useless for some other tasks.

I'm finding that laptops from the 2004-2006 era are really robust and 
seem to continue to just work and do their job sufficiently well to 
where my employer, a 501(c)(3) not-for-profit public foundation, is 
having difficulty getting donations of anything dual-core or better, and 
funding just isn't there yet to roll in newer stuff.  So the dozen or so 
D610's we have running Windows 7 get heavy use, and our few Core Duo 
Dell Inspiron 640M's and 9400's are still workhorses.  Hmph, I just last 
fall upgraded from a Dell D830 as my primary laptop, and I still use the 
D830/M4300's I have as CentOS 7 machines that are quite reasonable 
performers.  I'd love to get a dozen or two D830/M4300's donated, as 
long as they still have good video or are Intel video D830s.

Most end users don't need anything more powerful than a Core 2 Duo T8300 
or similar for most tasks.

I'll end this post with the following excerpts from a couple of 
still-in-production machines just to give an indication of how old 
things can really get in production in linux-land: one here, and one at 
a client, both of which are locked at the versions indicated due to 
various issues, mostly having to do with hardware support (no, neither 
of them are directly exposed to the internet, and, yes, the client knows 
how badly they need to upgrade, as do we.... but, both machines are 
doing their respective jobs, doing them well, and in these particular 
cases the time won't be funded to upgrade until they actually break...):

+++++++++++++++++++
[root at webcam4 root]# uname -rsvp
Linux 2.4.22-1.2129.nptl_24.rhfc1.at #1 Fri Dec 12 20:11:09 EST 2003 i586
[root at webcam4 root]# cat /proc/cpuinfo
processor    : 0
vendor_id    : AuthenticAMD
cpu family    : 5
model        : 8
model name    : AMD-K6(tm) 3D processor
stepping    : 12
cpu MHz        : 300.694
cache size    : 64 KB
fdiv_bug    : no
hlt_bug        : no
f00f_bug    : no
coma_bug    : no
fpu        : yes
fpu_exception    : yes
cpuid level    : 1
wp        : yes
flags        : fpu vme de pse tsc msr mce cx8 pge mmx syscall 3dnow k6_mtrr
bogomips    : 599.65

[root at webcam4 root]# cat /etc/redhat-release
Fedora Core release 1 (Yarrow)
[root at webcam4 root]#
+++++++++++++++++++
[lowen at intra1 lowen]$ uname -rsvp
Linux 2.0.36 #3 Fri Apr 9 15:36:11 EDT 1999 unknown
[lowen at intra1 lowen]$ cat /proc/cpuinfo
processor    : 0
cpu        : 586
model        : AMD-K6(tm) 3D processor
vendor_id    : AuthenticAMD
stepping    : M
fdiv_bug    : no
hlt_bug        : no
f00f_bug    : no
fpu        : yes
fpu_exception    : yes
cpuid        : yes
wp        : yes
flags        : fpu vme de pse tsc msr mce cx8 syscr pge mmx 3dnow
bogomips    : 999.42
[lowen at intra1 lowen]$ cat /etc/redhat-release
Red Hat Linux release 5.2 (Apollo)
[lowen at intra1 lowen]$
+++++++++++++++++++