Oct 172021

All the details of Apple’s M1X processor! Here first! Before Apple has announced it!

Yes this is just click-bait. Just like all the other videos/posts/stories or whatever about Apple’s soon-to-be-announced (perhaps) ARM-based processor that supposedly scales up more than the original M1. It’s going to happen sometime (which is probably on the 18th – tomorrow at the time of writing).

So where does all the early speculation come from? In all probability it is nothing more than speculation and click-bait. You’re wasting your time clicking on this story no less and no more than checking out the others.

Except this one is honest about it being just click-bait.

The Naked Horseman
Oct 162021

The one you’re running.

A bit of a simplistic answer but there’s a great deal of truth to it. It is too easy to get distracted by the new shiny and keep changing distributions. When the time could be far better spent just learning Linux – to a great extent all Linux distributions are the same. You can get Firefox (or whatever browser you prefer) with any of them; similarly LibreOffice is nearly always available. It’s the software you use on a daily basis that is important; not which distribution you’re using.

Similarly the desktop environment you use is selectable – this laptop has a distribution-specific flavour of GNOME, Awesome, Xmonad, and i3 (although I spend most of my time in Awesome). You might be able to tell something about my preferences for “desktop environments” from that list! A whole new desktop environment and a whole new look is just a quick software install away.

And a whole lot quicker and less disruptively than you can install a different distribution.

Different distributions offer different feature sets and different system administration commands (dpkg vs yum), but it isn’t that difficult to adjust to these differences especially when most of the time you are just using the computer to do real stuff rather than just managing it.

The Round Table
Aug 282021

Dealing with a potentially problematic SATA controller, I came across a little issue – which disks were connected to which controller? Not a problem most people would have to deal with but I do have rather a lot of disks. What I wanted was a tool that would list the controllers (lspci) with disks (block devices) shown per controller (lsblk).

I couldn’t find on, so I knocked up a quick and nasty shell script to do the job.

This isn’t a proper product and probably has many bugs (in particular it doesn’t like disks that are members of a volume group), but it works well enough for my use case :-

» ./print-block-tree 
01:00.0 USB controller: Advanced Micro Devices, Inc. [AMD] X399 Series Chipset USB 3.1 xHCI Controller (rev 02)
  sr0:  PIONEER BD-RW_BDR-UD04 41443030303030303030303030303030 1024M
01:00.1 SATA controller: Advanced Micro Devices, Inc. [AMD] X399 Series Chipset SATA Controller (rev 02)
  sdi: 0x5000c50050ada74d ATA ST4000VN000-1H41 Z300H9GD 3.6T
  sdl: 0x500003992be00c53 ATA TOSHIBA_MG04ACA4 39DFK8S4FJKA 3.6T
  sdm: 0x500003992bf8077f ATA TOSHIBA_MG04ACA4 39CIK7DNFJKA 3.6T
  sdn: 0x500a075102fce9c7 ATA C300-CTFDDAC128M 00000000103402FCE9C7 119.2G
  sdo: 0x500003992bb80ede ATA TOSHIBA_MG04ACA4 39CAKCKDFJKA 3.6T
09:00.0 SATA controller: Marvell Technology Group Ltd. 88SE9235 PCIe 2.0 x2 4-port SATA 6 Gb/s Controller (rev 11)
  sdp: 0x5002538f71100d76 ATA Samsung_SSD_870 S5STNG0R101271L 3.6T
  sdq: 0x50000399ec700c31 ATA TOSHIBA_MG04ACA4 30BXKC00FJKA 3.6T
41:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983
  nvme0n1:  96G
42:00.0 Serial Attached SCSI controller: Broadcom / LSI SAS2308 PCI-Express Fusion-MPT SAS-2 (rev 05)
  sdb: 0x500080dc00b4e2e9 ATA TOSHIBA-TR200 28RB76F7K46S 223.6G
  sdc: 0x500080dc00b4e3f6 ATA TOSHIBA-TR200 28RB76MOK46S 223.6G
  sdd: 0x500080dc009263fa ATA TOSHIBA-TR200 976B607GK46S 223.6G
  sde: 0x500080dc00926416 ATA TOSHIBA-TR200 976B6088K46S 223.6G
  sdf: 0x50025388a09508a9 ATA Samsung_SSD_850 S1SMNSAG216528K 119.2G
  sdg: 0x50025385a01c8379 ATA Samsung_SSD_840 S1ANNSAF214088T 119.2G
  sdh: 0x500080dc009263f4 ATA TOSHIBA-TR200 976B607AK46S 223.6G
  sda: 0x50025388a09508b4 ATA Samsung_SSD_850 S1SMNSAG216534V 119.2G
44:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) USB 3.0 Host Controller
  sdj:  Generic- USB3.0_CRW_-SD 201404081410 59.5G

The script itself :-

# Attempt at printing a "tree" of block devices

controllers=$(ls /dev/disk/by-path | awk -F- '{printf "%s-%s\n", $1, $2}' | uniq)
for c in $controllers
  rhs=$(echo ${c} | awk -F- '{print $2}')
  lspci -s ${rhs}
  blockdevices=$(ls -l /dev/disk/by-path/${c}* | grep -v part | awk '{print $NF}' | awk -F/ '{print $NF}' | uniq)
  for b in $blockdevices
    exp=$(lsblk -no WWN,VENDOR,MODEL,SERIAL,SIZE /dev/${b} | head -1 | tr -s " ")
    if [ -n "${exp}" ]
      echo "  ${b}: ${exp}"
The Rower
Aug 282021

For a while now, my workstation has been spewing out this error in rather large volumes :-

Aug 27 00:00:07 pica multipathd[1686]: pktcdvd0: unusable path (wild) - checker failed

(about 18,000 per day)

The multipath daemon is for handling block devices (disks) with multiple connections and dynamically updating the geometry when errors occur. Not the sort of thing that you usually find in a workstation (or indeed most servers) and indeed it appears that I only have this installed because I started with the server install of Ubuntu.

It wasn’t causing any harm but it was annoying that it was spamming syslog log files, so I took a look at fixing it. Turns out it is rather easy. Just edit /etc/multipath.conf and add a “blacklist” section :-

blacklist {
       devnode "^pktcdvd0"

The parameter to “devnode” is a regular expression but in this case we can get away with a “^” (meaning beginning of string) followed by the name of the device.

At this point, you could restart the daemon :-

systemctl restart multipathd.service

This shouldn’t cause any problems on most machines without multiple paths; and it probably won’t be a problem for servers which do have multiple paths. But in the later case, I’d test it or just go for a full reboot.

Morning Lighthouse
Aug 142021

Today if you are a Linux user and fire up a terminal window to “do something” at the command-line, you are using a gooey program to emulate an old terminal which was separate to the computer.

Today you are almost always using a keyboard and screen connected directly to the computer you are using and the gooey program you fire up as a terminal is in fact originally called a terminal emulator. That is, it pretends to be a real terminal.

So what were these real terminals?

The earliest “terminals” were actually teletypes for communicating text messages over long distances (over wires!). Not only was there no digital computer involved, but they predate computers by quite a way – the earliest ones were used in the late 19th century. And of course printed the text onto paper directly. The earliest digital computers used these teletypes as input and output devices, so you could type in commands and see the result immediately (or as quickly as the result could be produced). These early days still leave some traces today :-

✓ mike@Lime» tty

The “tty” command commemorates those old printing terminals – the “tt” in “tty” is short for “teletype”.

The speed and wasted paper of those printing terminals was a bit tedious, so the 1970s saw them gradually replaced with glass teletypes – which were basically keyboards and CRT screens built into an enclosure that would attach to a central computer over a serial line.

binary comment

These terminals (and showing an ADM 3A here is a little unfair as it wasn’t quite this simple) were really simple – they had exactly the same capabilities as the printing terminals. No cursor control (meaning no full screen editing), plain text, no italics or bold, etc.

Over time, more and more features were added to the terminal allowing more usable software (in particular the learning curve was not quite as steep). These features grew to accommodate colour, graphics, the ability to load and save data locally, and even the ability to function as a microcomputer (the HP pictured below could run CP/M in certain configurations).

But where did they go?

The heyday of the terminal was in the 1980s when many office-based companies were busy trying to put something like a computer on every desk, and a terminal connected to a central computer was one way of doing that. But they compared rather poorly with microcomputers – typically very slow in comparison, less likely to offer any kind of graphics (graphics was an option but typically cost as much as a microcomputer), and just wasn’t very “cool”.

Despite several attempts at resurrecting them (they were popular amongst those who had to centrally support them), they never really returned.

But they do survive inside modern operating systems in terms of a terminal emulator (as mentioned previously) to access the operating system command line – all three main operating systems (Windows, macOS, and Linux) have a terminal emulator of sorts. And Microsoft is actually investing in re-engineering their terminal emulator.

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