Questions about setting up a new computer

[John J. Boyer]

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
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Location: Madison, Wisconsin USA
Mission: To develop softwares and provide STEM services for people with 
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