[vcf-midatlantic] Monitor needed for museum

Dave Wade dave.g4ugm at gmail.com
Sat Aug 26 14:35:42 EDT 2017


I do know that PI's are famous for corrupting the boot disk. A couple of
work arounds, use a cheap phone booster as a UPS, 

http://raspi-ups.appspot.com/en/index.jsp


or change the PI to boot from USB stick.

An old article on this is here:-

https://samhobbs.co.uk/2013/10/speed-up-your-pi-by-booting-to-a-usb-flash-dr
ive

Dave



> -----Original Message-----
> From: vcf-midatlantic [mailto:vcf-midatlantic-
> bounces at lists.vintagecomputerfederation.org] On Behalf Of Jim Scheef via
> vcf-midatlantic
> Sent: 26 August 2017 14:50
> To: William Dudley via vcf-midatlantic <vcf-
> midatlantic at lists.vintagecomputerfederation.org>
> Cc: Jim Scheef <js at sdf.org>
> Subject: Re: [vcf-midatlantic] Monitor needed for museum
> 
> Could I ask a question? How often does this happen? Ok, two questions...
> what happens when the power goes off? (No talk about how reliable the
> power is at IA.) Just pull the f%^&ing plug and reboot the Pi. It has a
> journaling file system and will check the file system if needed. Why all
the
> fuss?
> Occasionally it might be a good idea to make a copy of the uSD card as a
> backup.
> Jim
> 
> 
> On Wed, 23 Aug 2017, William Dudley via vcf-midatlantic wrote:
> 
> > Date: Wed, 23 Aug 2017 09:31:40 -0400
> > From: William Dudley via vcf-midatlantic
> >     <vcf-midatlantic at lists.vintagecomputerfederation.org>
> > To: vcf-midatlantic
> > <vcf-midatlantic at lists.vintagecomputerfederation.org>
> > Cc: William Dudley <wfdudley at gmail.com>
> > Subject: Re: [vcf-midatlantic] Monitor needed for museum
> >
> > We are currently trying to install the shutdown button and associated
> > script, but couldn't install the script as we lost the ability to ssh
> > into the pi. So we can't power it down properly, we can't edit config
> > files, and we can't fix ssh without the monitor.
> >
> > Bill Dudley
> >
> >
> > On Aug 23, 2017 8:30 AM, "Neil Cherry via vcf-midatlantic" <
> > vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >
> >> On 08/22/2017 08:21 PM, David Ryskalczyk via vcf-midatlantic wrote:
> >>
> >>> I'll make an EE guess here: When you unplug the DC side, the Pi is
> >>> shut off relatively quickly so there is little room for bad writes
> >>> to corrupt the card, or for the voltage to drop low enough for the
> >>> CPU to execute random instructions but still high enough to run at
> >>> all. When you unplug the AC side of the power adapter, the
> >>> capacitance in the power supply causes a much slower drop-off which
> >>> causes the CPU to execute random instructions, likely writing to the
> >>> card.
> >>>
> >>
> >> I think the USB PS tend to be more inductive than capacitive.
> >>
> >> My suggestions? Make the Linux setup as read-only as possible as that
> >> will
> >>> minimize
> >>> possibility of corruption, and of course, if the image contents are
> >>> static, keep a copy of the image handy on a nearby PC. Constant
> >>> writing will quickly kill the SD card anyway.
> >>>
> >>
> >> This will help, you can setup a share using either NFS or Samba (CIFS).
> >> You can then write to that.
> >>
> >> But there are some things that need to write to files. The OS part of
> >> Linux generally doesn't need this but the applications (rsyslog,
> >> email, etc) does and they also tend to try and write out logs. That's
> >> a distribution issue.
> >>
> >> Pulling power from the DC end (that part that plugs into the Pi
> >> directly) is probably not a bad idea. But not until you've run the
shutdown
> cmd.
> >> So to properly shutdown the Pi, run the shutdown command or use
> >> Dave's suggestion of the pushbutton solution. I like that one but
> >> protect the button and don't make it a big red button that say don't
> >> push. People will want to push it.
> >>
> >> I'm sure there are more than a few of us with stories of idiots
> >> pushing the emergency power off on mainframes.
> >>
> >> --
> >> Linux Home Automation         Neil Cherry       ncherry at linuxha.com
> >> http://www.linuxha.com/                         Main site
> >> http://linuxha.blogspot.com/                    My HA Blog
> >> Author of:      Linux Smart Homes For Dummies
> >>
> >
> 
> js at sdf.org
> SDF Public Access UNIX System - http://sdf.lonestar.org




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