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Showing posts from November, 2023

Time Electronics 9814 Programmable Voltage Calibrator

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I left school having just turned 17 after my 'A' levels in 1980, needing to fill a year before going to University, and ended up working at Time Electronics in Tonbridge.   The company made electronic calibration lab instruments, and I worked there for a year before University, and then in most vacations subsequently until I started my first post-graduation job at DEC in 1984. More reminiscences about this in a future post perhaps. The biggest project I was involved with was a new range of programmable instrumentation, with remote operation via IEEE-488/GPIB and local front panel controls. This range included voltage and current sources, a programmable resistance, multi-way switch, and screwdriver *(1).  Later on, a multi-function calibrator was produced, combining several functions in one unit. Since I retired from actual paid employment a few years ago, I've been slowly collecting working versions of things I worked on during my career.  For example, using simh, I can run

Ubiquiti Edgerouter ER-X Flash issues (free space, hangs, firmware upgrades)

  The ER-X is a very cheap 5 port router, with a lot of enterprise-level software features. It's almost too cheap, because it doesn't really have enough Flash memory, and certainly with earlier samples, the Flash itself was rather unreliable. For a start, there isn't enough Flash space to store three images, so when you want to upgrade the firmware, you always need to delete any old backup version that's still installed to make enough free space ("delete system image" CLI command). The firmware upgrade process ("add system image") itself can be rather hit&miss on devices that suffer from unreliable Flash, requiring multiple attempts to succeed. The symptom I found is an apparent hang at the "Copying Image" stage, with a crash and reboot after a few minutes. There are many reports on the Internet of ER-X having random hangs with various software versions, in particular there's a symptom where IP forwarding seems to work normally, but