For various reasons I'm finally getting somewhat serious aboutplanning out a new PC to replace my current one , and this is forcing me to confront anumber of issues. One of them is the question of an optical drive.

I've had a succession of PCs over the years, and from the startthey've had at least one optical drive (initially CD-ROM drives andthen DVD drives). Back in those days it was somewhere between arequired feature (for reading CD-ROMs and

In a conversation on Twitter, I said :

EV isn't exactly a scam, but it is trying to (profitably) solve aproblem that we don't actually know how to solve (and have failed at).

The main problem that plain old TLS certificates solve is makingsure that you're talking to the real facebook.com instead of animposter or a man in the middle. This is why they've been rebrandedas 'Domain Validation (DV)' certificates; they validate the

After writing about our systemd reboot problem , I decided that I was irritated enoughto spend part of today trying to dig into the situation (partlybecause of all of the comments and reactions to my entry, sincethey raised good questions and suggestions). I don't have anydefinite answers, partly because it's quite hard to see thestate of the system when this is happening, but I do have someobservations and notes (and some potentially useful contributionsfrom other people on Twitter).

Here is

We just went through a periodic exercise of rebooting all of our Ubuntu servers in order to getup to date on kernels and so on. By now almost all of our serversare running Ubuntu 16.04, which means that they're using systemd.Unfortunately this gives us a real problem, because on Ubuntu16.04, systemd won't reliably reboot your system . On some servers,usually the busiest and most important ones, the system will juststop during the shutdown process and

Right now, our mail system basically puntson handling false positives (non-spam detected as spam). The onlything that users can do about false positives is turn off SMTP timerejection (if they have it turned on) and then fish the mis-classifiedmessage out of their filters or our archive of all recent emailthey've gotten . If themessage has already been rejected, the only thing that can be doneis to get the sender to re-send it. And there's no

I recently wrote about using the spam scores from another mailsystem at the university . In a comment,Robert Sander suggested that the original email system should havejust rejected the spam at SMTP time. There are a number of issueshere, but one of the traditional reasons not to do this is to provideyour users with varying levels of spam filtering ( which is somethingwe do ). This is a perfectly traditionalreason, but perhaps this is a copout answer (to be fair, an unexaminedone).

The

Up until now, I've been casually talking about systemd supportingper-user fair share scheduling, when writing about the basicmechanics and in things like gettingcron jobs to cooperate . But really both ofthese point out a fundamental limitation, which is that systemddoesn't have per-user fair share scheduling; what it really has isper-slice fair share scheduling . You can create per-user fairshare scheduling from this only to the extent that you can arrangefor a given user's processes

In my last installment on fair share scheduling with systemd andUbuntu 16.04 , I succeeded in workingout how to get ordinary user processes (ones spawned from peoplelogging in or sshing in or the like) organized into the right cgrouphierarchy so they would be subjected to per-user fair share scheduling.However, I discovered and noted a limitation that is relevant forour environment, which is that in a standard Ubuntu 16.04 system,processes started by cron are not put into user

One of the things about Git is that onceyou go past basic committing, it generally has any number of waysfor you to do what you want done. As with programming languages,part of getting better at Git is learning to pick the right idiomto attack your problem with. I can't claim that I'm good at this,but I am getting more experience, and recently I had an interestingexperience here.

I use Byron Rakitzis' version of rc as my shell, which these days can