RE: Advice Required - for avoiding conflict betwen qmail-smtpd, rblsmtpd loaded as shared objects in tcpserver

>I do think you're right about UNIX systems and caches; most Linux systems
also would have caches.
>
>On Sun, 2 Apr 2017 20:44:21 -0400, David T. Ashley wrote:
> Jens, the hardware and software scenarios you are considering ... wow 
> ... it is almost like you hacked/rooted your smart coffee maker and 
> are using it as a qmail server.
>
>Shhh... I planned on making money on converting coffee makers into mail
servers. ;)
>
>To tell the truth, I was thinking about Cortex-M (something like STM32F4)
as a miniature mail server.
>Sure I could just "port" the stock qmail, but that would only give me IPv4,
which means in the near future such a server would already be obsolete.
>The STM32F4xx microcontroller is based on ARM Cortex-M4 and runs at 168 MHz
or 180 MHz, which is enough for a normal home email server.
>It could easily store the received data on a SD card or MicroSD card. No
extra memory would be required as the STM32F4 has 192K on-chip RAM (or more,
depending on the model).
>
>Sadly, there's a problem with SD cards wearing out, which is one reason I'm
not so keen on starting the project.
>-But I think it would be cool to be able to purchase a ready-made email
server for $20, which you can just hook up and start using.

Hi Jens,

A colleague and I had struggled with the same issue, maybe for some of the
same reasons.

He wanted to use a Raspberry Pi as a home server.  There were obvious
hardware and software issues
to be addressed, and we discussed them.

My personal situation is that I had all of these criteria to meet:

a)Had to be noiseless/fanless -- it would sit in my entertainment center,
and I wouldn't want it to
interfere with my video games or Arnold Schwarzenegger movies.

b)Had to be compact.

c)Should run a standard Linix distribution--easy to upgrade.

d)Should support terabytes of storage, if I wish, with no wearout issues.

e)Should not use much power.  My target was 15 watts -- I'm glad I got a
solution at 5.5 watts.
This is under $10 a year -- excellent!

f)Shouldn't be too expensive.

g)Should tolerate power loss with no data corruption.

I looked at industrial computer boards, but these were expensive, and still
left the UPS issue unaddressed.

Finally, I settled on a Lenovo 11e.  You can pick them up at the Lenovo
outlet store for <$300, easy (just get
a Windows one so you know it has the bay and hardware for a hard drive).

The machine is fanless nearly all of the time.  (If I do load the CPU
heavily, the fan does go on, though, and the power
consumption can get as high as 15 watts.  But this only occurs when running
maintenance crons.  HTTP service
and so on won't do it.)

The UPS problem is solved automatically, as the laptop's battery acts as a
UPS.  In fact, I wrote a cron script
to shut it down if the power is off for too long and the battery's charge
falls too far:

http://e3ft.ddns.net/vvcdtapublic/dtapublic/projs/dtats/trunk/projs/20161029
_server_scripts_automaint_cron/power_fail_shutdown?revision=98&view=markup

For the URL above, I will give you one guess about how that is being served
LOL.

The approaches you are contemplating are very clever, but for me getting
essentially a slow PC for 5.5 watts of power consumption works the best.

Best regards, Dave A.