Questions about setting up a new computer

John G. Heim jheim at math.wisc.edu
Sun Jul 17 17:16:35 UTC 2016


I was going to say the same thinga bout getting 32 Gb of ram. The main 
reason most people get as much as 32Gb for their personal workstations 
is for on-line gaming. Or if you are into creating virtual machines you 
might be able to use 32Gb of ram. But here at the Math Department at the 
UW, the only machines we have with 32Gb of ram are used for research 
like modelling cloud formations. None of  our web server, mail server, 
database server, or file server have 32 GB of ram. I think you could 
combine all 4 of those functions onto one server and still get by with 
less than 32Gb of ram. If it was me, I'd spend my money on an SSD drive.

As for the cpu, at the Math department, we have bought nothing but Intel 
I5 machines for the past several years. It used to be that Intel and AMD 
would leapfrog each other with each new cpu release. But that hasn't 
happened lately. I think the money Intel has been abel to spend on 
research has put them ahead for good. I have a brand new PC on my desk 
at work but I turned it off for the weekend. I can't see the cpu model 
right now but I know it is some type of Intel I5. But the last 2 groups 
of machines we bought had Intel I5-4570 and I5-4590 cpus. If you are 
doing something that actually will use 32Gb of ram, you might get an 
Intel I7 processor to go with that. But again, I'd spend my money on an 
SSD drive.




On 07/16/2016 05:36 PM, Joel Roth wrote:
> Hi John,
>
> If  you are working in the console, you won't generally need high
> performance hardware.  If you compile a lot of software, or
> do disk intensive work, a solid-state disk is nice. I notice
> powerful processors make a difference in compressing video
> and any scientific computing.
>
> A big issue in new hardware is uefi vs BIOS booting.
> And in that motherboards shipped with the microsoft
> signed boot loading restrictions.
>
> http://www.rodsbooks.com/efi-bootloaders/secureboot.html
>
> BIOS has been around a long time, and easy to deal with
> in a linux environment.
>
> Have fun,
>
> Joel
>   
> John J. Boyer wrote:
>> Thanks for the information. I had forgotten some of the Linux terms,
>> such as swap file or partition. How do I go about setting up a tmpfs?
>>
>> The installation will be command-line only Braille only Debian. I might
>> add a desktop later, but I don't want it to be automatically loaded at
>> boot time.
>>
>> What CPU would be appropriae. I would guess something recent, but not
>> the latest.
>>
>> Thanks,
>> John
>>
>> On Sat, Jul 16, 2016 at 02:06:45PM -0400, Sam Hartman wrote:
>>>>>>>> "John" == John J Boyer <john.boyer at abilitiessoft.org> writes:
>>>      John> I've more or less decided to replacer my ten-year-old Linux
>>>      John> machine. It is giving error messages intermittently. Most of
>>>      John> them are about sector errors, but others seem to have nothing
>>>      John> to do with the hard drive. It may be more and more
>>>      John> troublesome, even if the hard drive is replaced.  Besides, it
>>>      John> would be nice to get more up-to-date hardware.
>>>
>>>      John> I'm thinking of getting 32 GB of ram. 8 GB will be for normal
>>>      John> use. The other 24 GB will be in a ramdisk.
>>>
>>> I think you must have a DOS background here.
>>> An explicit RAM disk is rarely if ever useful on Linux.  I'm tryinfg to
>>> remember if I even know how to create a block device backed by RAM... O,
>>> yeah, I can think of a way,  but you probably don't want to do that.
>>>
>>> Instead, you probably do want to create something called a tmpfs.
>>> That's a filesystem backed by RAM.  When your computer reboots all its
>>> contents go away.
>>>
>>> There are important differences between a tmpfs and a RAM disk.
>>> The biggest is that Linux will only use as much RAM as is needed by the
>>> tmpfs to store what currently lives in it.
>>> (You can set a maximum size, but with 32g I wouldn't bother)
>>>
>>> So, you can get the best of both worlds, storing your temporary files in
>>> RAM, but using RAM for RAM if you don't have 24G of temporary files at
>>> the moment.
>>>
>>>
>>>      John> Do I need a paging
>>>      John> file? 8 GB of available ram should be more than enough. The
>>>      John> paging file on my present machine always shows 0 usage, even
>>>      John> with only 4 GB of ram.
>>>
>>>
>>> Having a paging file has a couple of affects even if it is not used, but
>>> no, you probably don't want a swap partition or file (linux names for
>>> paging)
>>>
>>>      John> How do I avoid setting up a paging file
>>>      John> during installation? I'm using Debian Jessie.
>>>
>>> In expert mode, avoid creating a swap partition and if asked don't
>>> create a swap file.
>>> If you don't want to use expert mode, don't worry about it; having a
>>> swap partition won't be a problem.
>>>
>>>      John> How do i set up the ramdisk? I want to assign the temp
>>>      John> directory to it.
>>>
>>> I think the installer will do that by default.
>>> But in /etc/fstab you want a line like
>>>
>>> none				/tmp			tmpfs				defaults		0	0
>>>
>>>      John> It might be nice if the
>>>      John> bin, sbin and usr
>>>      John> directories were loaded onto it at boot-up.
>>>
>>> No need for that.
>>> Linux is also smart enough to cache files  as they are used, storing
>>> copies in memory, so no value in moving them to the tmpfs.
>>>
>>> The file will be loaded the first time it is used.
>>> You could do that at boot for /bin, /sbin and /usr, but you probably
>>> don't want to.  The reason is that the system is fairly busy at boot,
>>> and it would probably slow down things like bringing up your desktop and
>>> starting system services.  The only advantage of pre-caching files on
>>> boot would be faster performance the first time you accessed a program
>>> after pre-caching is done.  However you get slower boot times and slower
>>> performance during the pre-caching.
>> -- 
>> John J. Boyer; President,
>> AbilitiesSoft, Inc.
>> Email: john.boyer at abilitiessoft.org
>> Website: http://www.abilitiessoft.org
>> Status: 501(C)(3) Nonprofit
>> Location: Madison, Wisconsin USA
>> Mission: To develop softwares and provide STEM services for people with
>>           disabilities which are available at no cost.
>>
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