[labnetwork] Tool PC backups / PC redundancy

[P. Scott Harris]

Hi,

Just my two cents since we get involved with older equipment (specifically a 
line of GCA pattern generators and steppers) on a regular basis :

- PING (it's a Linux-based GPL mirroring/backup/restore utility on a bootable 
CD) does a reasonable job of mirroring PC hard drives to pretty much any other 
media including USB drives and network shares

- for things like SunOS on SparcStations, you can also do a mirror image of a 
disk to an NFS network (there is GPL NFS server software for Windows) just using 
the standard UNIX dd command. I've managed, without too much trouble, to get the 
contents of two SCSI drives in an XLS Stepper into image files on a Windows 
machine using this technique.

- for DOS machines running software and not talking to special hardware, DOSBox 
or any virtual machine software (QEMU,VirtualBox,VmWare etc) usually works 
pretty well. The backup requirements then amount to making a backup copy of the 
virtual machine disk file. SmartSet analysis software for GCA steppers will run 
happily under DOSBox

- you can run Windows in its various incarnations (XP,98SE etc) as a virtual 
machine. I have the most luck with VmWare but VirtualBox does a reasonable job 
as well. The backup requirement then again becomes just making a backup copy of 
the virtual disk file. Custom hardware drivers seem to work okay, at least for 
the ones that I have tried under XP but your mileage may vary. Windows software 
controlling a machine won't really be 'real-time' in the same way as DOS 
software so an emulation may still be fast enough.

- if the hardware interfaces are 'generic' then the virtual machine has a better 
chance of working. We do an Ultratech XLS stepper (originally built around a 
SparcStation2) upgrade with a virtual machine running on a Windows/Linux host 
but the interfaces to hardware are just the standard serial ports and network 
connections (admittedly 10base2 but there are adapters to get from coax to RJ45)

- we run PDP-11 emulations for a line of GCA steppers under DOS but the 
connections to the actual stepper are standard serial ports and a conventional 
parallel port to our own hardware interface to the stepper. The motherboard then 
can be whatever is available (DOS will boot on pretty much anything) and backups 
just involve copying files to some safe location. mTCP is modern freeware that 
will set up DOS as an FTP server so that you can get files into and out-of the 
DOS machine without much difficulty

- for older PC based systems (usually involving ISA bus peripherals and DOS) the 
problem can generally be more about getting CPU speeds that keep the software 
happy. There are still lots of industrial suppliers of motherboards with ISA-bus 
support but the CPU clock speeds are the usual 1.5GHz and higher. Older DOS 
software, written for 40MHz 386 CPUs (DFAS software for GCA steppers comes to 
mind) can get very cranky at high CPU clock speeds. If the DOS system is doing 
real time control then virtual machines may not be useful but if the priority of 
the DOS emulation is high enough and the the host CPU speed is fast enough then 
the virtual DOS machine might still be worth evaluating.

So for older systems (and no question that it will totally depend on the 
system), it might be worth evaluating some kind of virtual machine for the PC 
tools since the hard disk problems go away, disk backups just become file 
backups and old operating systems can get moved from one motherboard to another 
while the virtual peripherals stay the same. Some of the virtual machine 
software (e.g. QEMU, DOSEMU, DOSBOX) come with virtual CPU speed adjustment 
which may help in certain situations. The evaluation is pretty risk free since 
most Virtual Machine software is free (VmWare has commercial software as well) 
as is the software that will make image copies of the necessary hard drives.

On 2014-11-13 10:16 AM, Shivakumar Bhaskaran wrote:
>
> Hi ,
>
> At UIUC We had three Plasma Therm PECVD/RIE tool, one of them were from 90s 
> and OS is windows98 and the CPU was aging we had issues with the hardware, we 
> tried replacing the hardware but was not successful, we purchased a new CPU 
> from the Plasma Therm to see whether it will support the old plasma therm. 
> With little bit effort from IT folks and spending more time in upgrading the 
> software and tried to configure the communication port we were able to make a 
> backup. So we have one CPU unit (this will be a spare one) and three backup 
> hardware (for three tools). So without any worries we were confident that we 
> can replace the CPU if it stopped working. As I said I didn't get immediate 
> solution, this took us more than 3months to figure this out (this was mainly 
> due to the tool was always in use, I had difficult time to test the unit with 
> upgraded software)
>
> This might help for some tool but not all, we might be little bit lucky to see 
> this worked out.
>
> --Shiva
>
>

-- 
Best regards,

P. Scott Harris, P.Eng.
H&L Associates
21 Parkmount Crescent
Nepean, Ontario K2H 5T3 Canada
Tel: (613) 828-1462
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