u/TheQuickFox_3826

KLTV (East Texas) recently interviewed Fritz Hager, the medical physicist at the East Texas Cancer Center who investigated the 1986 radiation overdoses with the Therac-25 radiotherapy machine. Although the technical causes of the Therac-25 have been documented for decades, this interview adds valuable first-hand historical detail from one of the key people involved.

A few things that stood out to me:

• Hager describes how he and a technician spent hours after work trying to reproduce the infamous "Malfunction 54" error.
• After successfully reproducing it, he measured a dose of about 15,000 centigray delivered in one-tenth of a second (far beyond a therapeutic dose.)
• He then asked MD Anderson's Dr. Robert Shalit to independently verify the measurement before reporting the findings.
• Rather than waiting for a coordinated response, Hager personally called every known Therac-25 site in the U.S. to warn them. Within hours, physicists at other hospitals were able to reproduce the same fault and connect it to injuries they had already seen.
• The article also includes what appears to be a photograph of the brief Cherenkov flash observed during one of the reproduction tests. I'd never seen that image published before.

One detail I found particularly striking is Hager's explanation that the earlier Therac-20 would simply blow a fuse if a similar operator sequence occurred because it still had hardware interlocks. The Therac-25's reliance on software in place of those interlocks is, of course, one of the central lessons of the case.

If you've only read Nancy Leveson's classic paper or watched the various YouTube explainers, this interview is a worthwhile complement.

I'd be interested to hear from anyone in medical physics or radiation oncology: is the Cherenkov photograph included in this article already well known within the field, or is this the first time it's been published so prominently?

The Android versions newer than 46_45 give a new "Privacy Consent" (Cookie permissions) screen at startup. My phone has privacy filtering features such as the NetGuard firewall. (Ad filter) This was preventing the screen to be loaded, most likely because it was being loaded from an ad server. When I disable the firewall or ad filter then the game loads, gives the consent screen at startup in which I set my consent preferences. Then the game started normally.

I now can re-enable my firewall and the game continues to work fine.

My phone was unable to display the new consent window and because of that the game quit at startup.

So if you have this issue, try to temporarily disable any firewall, network filtering, privacy filtering or ad blocking and see if a consent screen arrives. Set your preferences. Enter the game and then you can re-enable your filtering if you want.

I updated an Android game with the play store. The game now crashes. It still crashes then I reboot my phone, clear the cache and data of the game. The previous version worked fine. I sideloaded the previous version but it tells me to install the app from the play store. How do I install the previous version from the play store?

In the 1990s and 2000's the recommendation to e-mail users always was to delete old e-mails to save disk space, save server mailbox space (if the mail is stored on a server) to prevent slowdowns of the e-mail program/client and to reduce the chance of mailbox corruption. If e-mail old e-mail needs to be kept then the advice was to make a separate archive.

 

Is this still a general recommendation? With my private e-mail I never did this by choice. I'm using pop3, store mail on my PC. Not on the mail server. Have regular backups. And I'm very happy I did not comply because I love to have a digital trail of my personal e-mail history all the way back to 2001. I find it nice to see what happened when, or dig up old attachments if I need them after 10 years.

 

I delete obvious junk and mails that I obviously will never need to read again and once every few years I sift through the old mail to selectively delete some things I will never need again but keep the rest, and that is the majority. I few years back my Thunderbird mail client became a bit sluggish but then I switched from MBOX to Maildir storage which completely fixed this.

 

At work I do the same until the sysadmin tells me to do otherwise. Mail sits at the server there so storage space is more restricted.