[ydl-gen] Linux yellow dog manual for dummies

[Warren Nagourney]

I think one needs to distinguish between the OS and the CPU. My  
experience with the G5 is that its floating point performance is  
between 1.5x and 2x as fast as the equivalent x86. Unfortunately, the  
fixed point advantages are not there. I use LaTeX a lot and heard that  
the typesetting speed improved on Macs (running OS X) when Apple  
switched to intel (same TeX source - this might me in part a  
reflection on the poorer PPC optimizations in gcc).  The intel  
advantage might be 20% in LaTeX typesetting (this is a single data  
point from a commercial TeX).

On the other hand, the performance of the OS is another matter. Every  
linux I have installed on a Mac (or PS3) was much less responsive than  
OS X for similar operations. This is a combination of things like  
application launching speed and particularly graphics operations,  
which are slow in PPC linux since there are no good PPC drivers for  
video cards in linux.  This is entirely a user interface issue and a  
PPC linux server might do very well compared to the competition (I  
have no experience with this). Of course, the speed of apps which  
don't use graphics should be the same between linux and OS X since  
they both use the same compilers.

Cheers,

Warren Nagourney

On Dec 26, 2009, at 8:09 AM, Rob Sanders wrote:

> I haven't done much with YDL in some time as I've changed jobs, but  
> I'd just like to chime in that several years ago that the PPC  
> Linux's ( YDL for Mac, full RedHat/SuSE on some IBM OpenPower720  
> hardware) was running rings around the equivalent x86 -or- Alpha  
> based platforms we were doing some work on.  Tried to get my bosses  
> & customers more interested in it and hit the wall of 'but it isn't  
> x86'.  <sigh>.  At the time, a direct comparison of the *same* base  
> code on a Mac XServe G5 running on YDL4 vice OS X 10.3 had the YDL  
> code twice as fast as the OS X code.  Lots of double precision  
> floating point math, and multiple processes (not threads)  
> communicating via shared memory.  We would routinely max out any box  
> we were running on.
>
> -Rob
>
> On Dec 25, 2009, at 2:37 PM, Warren Nagourney wrote:
>
>> Thanks, Derick.
>>
>> Although this is a YDL forum, I am afraid to say that there is no  
>> comparison between any linux on PPC and OS X. The former simply  
>> doesn't have the software base that I need. I used to think that it  
>> would be faster than OS X, but after a few installations of linux  
>> on Apple computers, I discovered that OS X wins hands down in the  
>> speed area as well. I think that linux is optimized for x86 and of  
>> course things like flash are only available on x86 linux (I hate  
>> flash, but it unfortunately has become a standard for internet  
>> video). There are still some PPC optimizations in OS X apps and  
>> maybe even some Altivec usage (which allows Quicktime to smoothly  
>> run at 1080p on my PPC machines). The tasks involved in writing my  
>> book would have been enormously greater if I had used linux instead  
>> of OS X.
>>
>> I notice an increasing dominance of ARM in low power portable  
>> devices. This is unfortunate, since ARM simply doesn't have the  
>> computational power that PPC has - I am not sure it even has a  
>> floating point data type. It is too bad that IBM did such a poor  
>> job of promoting PPC; we will need to reinvent the wheel with ARM  
>> when we could have had advanced multi-purpose chips with low power  
>> consumption from the PPC manufacturers (such as PA semi, which  
>> Apple bought and converted to ARM).
>>
>> Anyway, the improvement in the performance of Apple products since  
>> the switch has been less than stellar, much less than expected from  
>> Moore's law. My 4 year old G5 has a 1.15 GHz memory bus and an 16x  
>> dual layer superdrive, which is very competitive with the best that  
>> Apple can come up with now (for reasonable prices). It cost much  
>> less than a current machine and doesn't require a several thousand  
>> dollar investment in software, which I would need to make if I use  
>> one of Apple's intel superboxes.
>>
>> Cheers,
>>
>> Warren Nagourney
>>
>> On Dec 24, 2009, at 2:28 PM, Derick Centeno wrote:
>>
>>> You may want to know that you may find decent parts for your system
>>> from http://macsales.com/
>>>
>>> I think we may have to really keep our PowerPC running for longer  
>>> than
>>> that although I did hear of someone developing a multicore PowerPC
>>> laptop a month or so ago.  I've got to search for who this fellow is
>>> again as I lost track, but I did hear of a fellow who created a  
>>> working
>>> Cell based laptop which ran the GameOS and had the OtherOS option.
>>> Pretty neat!
>>>
>>> Caveat:  If you replace the power supply or other support parts you
>>> shouldn't have trouble running YDL from it.  Be careful regarding  
>>> other
>>> components however such as DVD drives: if those go it may be wiser  
>>> to
>>> consider an external DVD drive in that situation.  I'm unsure if  
>>> anyone
>>> we knew remains at Fixstars from TSS; it may not be so easy to get  
>>> the
>>> kind of support we became accustomed to.  In any case, I'd advise  
>>> you
>>> to consider reviewing what notations remain regarding their  
>>> advisories
>>> regarding which hardware works with YDL and which do not.  As best I
>>> recall, the past emphasis (by TSS) was to support original Apple  
>>> parts.
>>>
>>> So the problems to watch for may not be RAM as much as internal
>>> associated devices, such as a newer hard drive or modem or something
>>> similar.  It may be better to just get an HD which resides on a PCI
>>> card which your system should recognize with no problem as an  
>>> external
>>> system; I don't think such a drive would be able to be booted from
>>> within YDL.  It would be interesting to try that out as a concept
>>> though.
>>>
>>> Anyway enjoy and all the best!!
>>>
>>> On Thu, 24 Dec 2009 13:57:49 -0800
>>> Warren Nagourney <warren at phys.washington.edu> wrote:
>>>
>>>> Thanks, Derick. I  still love the PPC architecture and recently
>>>> bought an Apple dual core 2.3 GHz G5 for very little money and am
>>>> finding it to be absolutely as fast as I could ever hope for. I  
>>>> will
>>>> keep it for the next 3-5 years (assuming I can keep the power  
>>>> supply
>>>> running) and maybe then, the dominance of x86 may have lessened (it
>>>> can't last forever!).
>>>>
>>>> Merry Christmas and Happy 2010,
>>>>
>>>> Warren N
>>>
>>>
>>>
>>>
>>> =========
>>>
>>> Refranes/Popular sayings:
>>> The Taino say:No hay mal que por bien no venga.
>>> There is no evil out of which good cannot blossom.
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>>
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