Google, as you may or may not know, it watching you. They are also watching you when you’re signed out.
OK, so, say you want to sign out of Google. You’re in say Gmail.
You know that if you scroll to the bottom of your list of messages you’ll see a tiny tiny tiny little box labelled (somewhat vaguely, probably on purpose) ‘Details’. If you click it, you get details of all your recent sessions on Google platforms (that’s the right-hand side of the picture).
OK, so you click the ‘Sign out all other web sessions’ button, close the dialogue box and then log out of the Gmail (or whatever) session you’re in. You are now free of Google.
With all your sessions logged out, try going to:
Click on the first entry — Your Google Search History. You’ll see something like this:
So now even though you’re logged out, there are more setting to try to control how your data are harvested. It’s is almost impossible to reduce the amount of data they suck out of you when you go online, but I hope this helps a little. (Note how they encourage you to log in.)
.Having bought the AlphaSever 1200 and got it to boot, there were a couple of things I wanted to do with it.
First, I wanted to put OpenVMS on it, which I’ll talk about elsewhere.
Second, I wanted to put something modern on it if possible.
A look at Distrowatch suggested that I had three options, effectively; OpenBSD, NetBSD and Gentoo Linux. A bit of poking around revealed that OpenBSD would work, but without X windows. Now, that’s a perfectly valid option — the machine could actually work as a server. But for me, as a user who wants to monkey around and use the machine for more desktop-y stuff, that was not what I was after.
Since the SRM console can only boot SCSI drives, and the machine had some unused SCSI drive caddies ready to go, I decided I’d have to spend more than the $1 I had so far. I found a chap on ebay who had a couple of 300GB SCSI hard drives — and even better, HP/Compaq ones, the entity that had absorbed Digital. I didn’t need postage and in the end I scored 2 x 36.4GB and 1 x 300GB drives, perfect since I had 3 unused caddies.
I’ve got to hand it to the whole SCSI thing. No setting jumpers, no master and slave, no two only per socket like IDE drives; I just plugged the drives into the cabinet and when I next booted up SRM found them and gave them identifiers — dkb300, 400 and 500, the latter being the 300GB.
I had three disks. My options are NetBSD and Gentoo. Is there a third option? I could try for Windows NT 4.0, which shows up on ebay sometimes. But I’m not really interested in old versions of Windows … but old versions made me think.
I use Debian on my main desktop machine and on my Netbook. I had read somewhere during my recent researches that Debian supported Alpha up to 5.0 ‘Lenny’. With Debian’s relatively long-term support, the last Lenny update (5.0.10) was as ‘recent’ as 2012. That’s a while back, but it’s hardly ancient.
What’s more, Debian might not be considered especially user-friendly but compared to NetBSD and Gentoo it certainly does hold your hand. After too much time looking at NetBSD and Gentoo, I decided I’d start with Debian. If I could get it to work, get a working xorg.conf, for example, then I might find out some stuff that would be useful with the more hands-on installs.
The installer uses a generic kernel, but there’s an SMP one in the repositories.
(1) Hunted around on the web and eventually found the Debian archive (archive.debian.org, oddly enough), and within that CD images for the first 6 of the 27(!) disks that made up the full Debian catalogue for Debian 5.0 (‘Lenny’) on Alpha. Downloaded the first 6 disks using a fast unmetered connection, plus the LXDE/XFCE disk and the KDE disk. Some direct download, some jigdo. Though I had internet on the machine, it is slow and expensive where I am. Also, I don’t need to worry about security updates, since Lenny is frozen, so a static CD repo is fine.
(2) Burned disk 1 and put it into the CD drive and booted into the SRM console. Typed:
P00>>> b dka400:
then at the aboot prompt chose kernel 0.
Soon the familiar Debian ncurses install screens started coming up and filled me with confidence.
(3) Set hostname and decided to install to 36.4GB disk, dkb400, which Debian knows as /dev/sdc.
(4) Created new partition table. Create ext3 root (/) partition of 34.4GB at ‘end of drive’. Then create swap of 1.8GB at end of available space. Then create 180MB ext2 boot partition (/boot) at end of the available 200MB and then in the last 20MB, right at the front of the disk ‘cos we’ve filled from the end forward, 20MB aboot partition.
This structure was chosen because (a) you need a small space at the front to install aboot, the bootloader Linux uses to boot on Alpha (aboot = Alpha boot), and aboot cannot boot an ext3 file system but can boot ext2, Hence the 180MB /boot partition. But I like the journalling of ext3, so I don’t want the whole drive ext2. I did not bother with a separate /home partition.
I considered a complex structure whereby all three OSs (this, Gentoo, NetBSD, should I get them working) would mount the same big /home file system from the 300GB drive, but I’m still experimenting. That could still be possible later, depending on how I chop up the 300GB drive.
Turned on bootable flags on aboot and /boot partitions. Don’t know if must, but did.
(5) Root password added and created my own user account in the usual way.
(6) Scanned in the CDROMs, or at least all the ones I’d bothered to burn — this sets up apt-get to know which disk each package is on, to allow install from CD. I can still set up a mirror for the odd thing that’s not on disk, but I decided not to do that yet. I’d like to keep my internet use down for now.
(7) Selected and installed software — ‘Desktop environment’ and ‘Standard system’ only. Watched it go, reading the files off the (fairly slow) old SCSI CDROM drive. Install needed disks 1 and 2 but no more.
P00>>> b dkb400:
Booted straight into working X login (gdm)! Amazing, Debian is ama … hang on, if I drag a window around the screen it gets blurred out and repeated in random places … uh oh. I hate debugging xorg.conf …
Look at /etc/X11/xorg.conf — it is a bare bones one, with most stuff done automagically.
(9) In the end, the solution was to go into the xorg.conf and reduce the colour depth. I say that in one line but it took me a while to figure it out.
The old video card (a VGA-plug Matrox Millennium MGA-2064W-R2 from 1995) is actually a pretty good piece of hardware, especially for its time. At a colour depth (DefaultDepth 16 in the relevant Screen section of xorg.conf) of 16 bits, it gives me modes all the way up to a frankly impressive 2048×1152, which is way beyond what is listed in the technical documentation for the card! (1600×1200)
I haven’t tried anything demanding in video terms yet, but all the modes work now. For reference, Debian current (9.4) running on amd64-type hardware and using the DVI-D cable runs at the monitor’s full resolution of 2560×1440. 2048×1152 from a card from last century seems more than I had any right to expect.
(10) In terms of software, most of the usual stuff seems to be there; LaTeX, various window managers, terminals, graphics, sound and video manipulation programs. Brasero, Audacity, xfce, KDE, Gnome (and it’s Gnome 2, which seeing as I use MATE on my more modern machines is completely fine), FLWM and Gimp and so on and so on. Even DOSbox, which emulates an old Intel x86 processor. There’s no OpenOffice, but even if there was it would be version 2.4, and I don’t think Open/LibreOffice had really hit its stride by then. KOffice is there (this is pre-Calligra) and is useful, and so are Abiword and Gnumeric. A lot of the tools I use routinely have hardly changed in 10 years (links, LaTeX, xFig). Probably the age is most apparent in the office software and the web browsers (especially Iceweasel 3.x, which is functional but a security issue).
(11) Installed the Debian package containing the SMP kernel, updated the soft links from initrd and vmlinuz to point to the SMP versions, and that was that. Hint: before rebooting, make sure that aboot.conf also has entries that point to the previous, working kernel and initrd in case something goes wrong.
Thinking about the Debian infrastructure — the servers, the mirrors, the fact that all these CD images can be reconstructed all these years later and used on what is not a current architecture, it’s all pretty amazing to me. That kind of thing can only happen when enthusiasts are empowered.
To get it all to work and only needing the one fix — the xorg.conf pixel depth — is remarkable.
The next thing I’ll try is the more modern Debian available through the efforts of the amazing people behind Debian unofficial ports. The key website seems to be this one: http://backup.parisc-linux.org/debian-alpha-archive/debian-cd/
Sorry: The wretched tale of Little Stevie Wright by Jack Marx
This is an odd book. My gut reaction to it is distaste. Marx paints both himself and Wright as untrustworthy junkies — which is most likely true — but in doing so he expends a lot of words on himself — for a biography, it’s remarkably autobiographical. Whether this reflects an inability to get much useful material out of Wright, or rampant ego on the part of the author, it’s hard to tell. Perhaps it needs to be viewed as the book plus the ‘making of’ documentary all rolled into one. In fact, that’s what it is.
The structure consists of alternating sections, one lot following Stevie Wright through his — yes, wretched — life, the other following Marx as he deals with Stevie and Fay(e) and tries to get material for the book.
I’ll discuss them separately.
The main problem with the actual biography part is that it lacks detail and dates. It’s just not a very good biography. Are we in 1969 or 1967? Is it 1975 or 1972 or 1979? It’s impossible to tell. Only by reference to some external source — like the internet — can the reader actually get a sense of when any of this happened. There’s no context half the time, just a narrow focus on Stevie and his drug problems and the emptiness of his life. OK, that’s important — but it’s not everything.
To his credit, Marx evokes the junkie life pretty vividly. Correctly, I can’t say. There’s a core of analysis in the work that seems valid — that Wright spent his life looking for easy answers, waiting for things to go his way, and the quick fixes he indulged in along the way turned from being the means to being the end in getting through life. After the Easybeats, did he make a new path for himself in music (like Vanda and Young)? No. Did he consciously give it up and get a ‘real’ job and work at it like a grown-up, like Snowy and Dick Diamonde? No. Things sometimes fell his way — Jesus Christ Superstar, Hard Road, ‘Evie’ — and often didn’t, and he wasn’t equipped for the mundane slog.
So that half of the book is an intermittently insightful, intermittently evocative narrative that hangs in the air, without context, without grounding in time or space. Interesting, but weak.
The other half … is not that good.
We follow Marx as he stays with Wright and his woman, Fay(e). Marx feeds them money in return for promised cooperation on the book, cooperation we never actually see although near the end he refers to his tape recorder so presumably he has got something out of Wright. Marx drinks, shoots up, mistreats people and generally paints himself as someone most of us would not want to associate with. He indulges in long vignettes that have little or nothing to do with the subject. He seems keen to tell us, basically, how immersed he was in the gutter and presumably this makes his comments on Wright more credible. I don’t know. I should say I have never been a fan of the ‘presenter as star’ kind of thing. It’s like one of those nature documentaries where all we ever see is the presenter telling us how hard it is to find the animal of interest. What it amounts to is padding, making the tiny little bit of real footage go as far as possible.
This is like that. It’s like Marx realised he did not have a whole book, so he’s padded it out with his own adventures and his list of attempts to get the story — all of which are essentially the same (he gives them money, they blow it on drugs, they ask for more money).
Lastly, it’s not clear what if any of the content was actually provided by Wright. Some is very personal, so presumably some of the book comes from actual interviews. Much of it reads like a potted version skimmed from elsewhere and then padded out by Marx’s attempts to guess what was going on inside the band or inside Wright’s head. There are no sources given, so we can only assume it’s either all from interviews or partly from interviews and partly made up, or it’s been gathered from other sources but Marx is too lazy to document them.
If this is ‘gonzo’ journalism, you can have it.
If you want to know what it’s like being a junkie trying to cadge information out of a junkie, it’s a very handy book.
Of course, the Easybeats were a great band, we must never forget that.
My (now aging) desktop machine runs Debian current perfectly snappily. It’s an i7-2600K with 8G RAM and a couple of TB HD. Nothing exotic these days, though when I first got it Debian was not up to date enough and I had to install a backports kernel — far too much work for my liking.
I’ve been having some issues with flaky HD access, and while I think it is a slightly poor motherboard (bad SATA connectors or something — I’ve tried many cables), I figured I was running an oldish BIOS version and a newer one might be better.
Now, flashing BIOS is a bit scary. If it goes wrong you can brick the machine. But when I saw that the newest version (even if 5+ years old) was F8 and I was running F3, I figured it might be possible that there was a bug or something that had been fixed in one of the 5 newer versions.
Read about Qflash:
Seemed OK. Just find the file, copy it to USB stick, reboot, hit ‘End’ while powering on and then follow the menu prompts.
The BIOS image I found on the website was:
(Gigabyte GA-H67MA-USB3-B3 is printed on my motherboard).
Downloaded, copied it to USB and in my ignorance rebooted. First I followed the instruction in the PDF and saved the old BIOS image to the USB stick, and then I realised I could not find the new one.
Exited without making any changes and revisited the website.
Looked closer at the file names in the Qflash examples (in PDF noted above) and realised they look nothing like mb_bios_ga-h67ma-usb3-b3_f8.exe; took a guess — maybe the exe file is a Windows self-extracting archive. Yes, it’s obvious to you, but I’ve not done this before, not much.
But I am on Debian … not Windows. Tried just unzipping it ($ unzip mb_bios_ga-h67ma-usb3-b3_f8.exe) but unzip did not like that. Threw errors.
Went to folder where mb_bios_ga-h67ma-usb3-b3_f8.exe was kept and:
$ mkdir flashbios $ mv mb_bios_ga-h67ma-usb3-b3_f8.exe flashbios/ $ cd flashbios/ $ wine mb_bios_ga-h67ma-usb3-b3_f8.exe
Wine (which is apparently not an emulator), ran perfectly (version 1.8.7) and yes some files leapt out of the exe file. So:
$ ls autoexec.bat FLASHSPI.EXE h7mausb3.f8 mb_bios_ga-h67ma-usb3-b3_f8.exe
Now, there is another option.
These are ‘7zip’ files, so can also type:
$ 7z e mb_bios_ga-h67ma-usb3-b3_f8.exe
where ‘e’ means ‘extract’. Whatever. Both work. I only figured out the 7z thing after first running Wine because it popped up a dialogue box that said ‘7z self-extracting archive’.
OK, so the file I need is h7mausb3.f8 (note it sticks to DOS 8.3 file naming rules).
Copied that file to the USB, rebooted and it all went smoothly.
Whether I have solved the issues I was having I don’t know (and actually I doubt) but the machine’s working, so that’s something.
Ebay for 99¢, though I paid $1. Came with:
Alpha 21164 chip, 2 of
1 GB RAM
35 GB SCSI HD
2 x SCSI CDROM
1 x 3.5″ floppy drive
DEC ethernet card
VGA card (Matrox something or other)
PCI SCSI card (I won’t use) (PCI to UltraSCSI adapter Qlogic ISP10X0)
PS/2 ports for keyboard and mouse
COM and PAR ports as usual
1 x IDE PCI card with a 20GB HD attached (not working)
The IDE card is not detected by the SRM console or the BIOS, so cannot be used to boot, but operating systems can find and mount it, so can be used for storage.
I did have to solder a little component, an inductor I am guessing, back onto the PCB of the 20GB IDE HD to get it to work, but work it does. (The IDE HD was in a rubber sleeve. Slipped it out of the sleeve and a little plastic-coated inductor fell out. Lucky it was not lost.) Found a second old IDE HD and put the two onto one of the IDE sockets on the PCI card, one as master one as slave. Not seen by SRM, sadly.
One of the SCSI CDROMs did not work, so instead I put a CDRW/DVDR onto the second IDE port. That gives me one CDROM that the BIOS can see to boot from to install media, plus something that can write data.
It has lots of PCI slots (no PCIE) and one (or is it 2?) EISA slots, which I put an old Ad-Lib card in, just ‘cos I had it lying around. I have no idea if it’ll work or be good for anything if it does.
So now the system has
1 x SCSI HD (35 GB) (plus three empty caddies)
2 x IDE HD (20 and 28GB)
1 x SCSI CDROM
1 x IDE CDRW/DVDR
1 x 3.5″ floppy
No USB; could try a USB PCI card, but can’t be bothered right now.
These machines had no integrated network or sound on the motherboard — they weren’t for desktop use, though they were sold as work stations.
When I got it this one did not boot. Hence $1.
Got it home — weighs a tonne — and plugged in the two power cables (one for each power supply) and a VGA cable which I ran to an old CRT monitor.
It started, the LCD on the front did a couple of checks then complained about power supply 1 (I think it was 1), then shut down.
Removed power supplies, tested fans — one had spider nest in it. Cleaned it, gave all the plugs a good wiggle and drove the fan for a few minutes using an external voltage source (toy train transformer connected directly to the fan inputs) to loosen it up. In my experience, these fans have very little torque, so a tiny bity of gunk can stop the fan spinning up and throw off the whole system. Giving it a clean and starting it with a finger push and letting it run for a few minutes can fix the problem.
And, yes that was enough. It booted up into AlphaBIOS, and then I had to start googling. I got it to boot into the SRM console, which is a sort of Unix-y VMS-y command line environment from which the boot process can be managed. (Note: If you are in AlphaBIOS and want to switch to the SRM console, press the Reset button (middle), wait 5 seconds, then press the Halt button(right).)
When I tried to boot, I got BIOS CHECKSUM error.
So I figured I had to flash the firmware. BUT…
That was pretty tricky. I’ll talk about that next time.
Anyway, in SRM if you type (P00>>> is the prompt):
P00>>> show dev
you get a list of the devices the console can see, labelled in OpenVMS style.
On this machine, it includes:
dka400: the SCSI CDROM ewa0: the ethernet card dkb0: the SCSI HD dva0: 3.5" floppy drive
These are the devices available for booting. It looks like this machine used to have Windows NT installed, which was available for Alpha up to NT4.0. My intention is to install OpenVMS through the hobbyist program and get a second SCSI HD and put Gentoo, NetBSD or OpenBSD on it (these are the only options for Alpha architecture these days; well, I guess Linux from scratch is an option, but I don’t hate myself that much…).
Note that the quote marks work fine if I force ‘straight quotes’ rather than smart ones — the is my mistake, not the font author’s…
Font of the week: Glass TTY VT220, a font to look like a DEC VT220 screen, obtained by reference to how the glyphs were actually implemented by the CRT.
File is: Glass_TTY_VT220.ttf
Available from: http://sensi.org/~svo/glasstty/
Here’s an example, just screengrabbed from LibreOffice — and I forgot to turn off curly quote marks..
Here’s the text:
Hello, here is my amber screen, looking pretty good, eh? The font is Glass TTY VT220, available from http://sensi.org/~svo/glasstty/.
It is designed to mimic what you’d see on the screen of a DEC VT220 serial terminal from about 1985. Not all the characters are available, although everything that could be entered on such a terminal is there.
You’ll note the quote marks don’t quite cut it, but otherwise it’s pretty nifty.
As noted, the quote marks do cut it. Maybe I’ll suck it into FontForge and see if I can come up with some ‘smart’ quote marks that match the spirit of the font.
Monarch by Remington, made in Holland in the 1960s. It was $5 and said ‘not working’ at the local recyclers. Turned out whoever put the label on did not know how to use the carriage lock. Needed a clean and the case has no base, only the lid and some ancient crumbling foam. The unit itself is very nice. Tabs, V-shaped paper stand, everything seems to work.
Character set shown below.
Ser. No. is hard to read; I think it is TY 487575, which puts it in 1965.
Keytops seem small and highly shaped and take some getting used to. Came with metal slot-together spools and a quite usable ribbon.
Not the most stylish of machines, but seems like a very useful typer. As bought some bowls and counters were clogged up (‘o’ looked like a solid black dot, for example), but the tip of a fine pair of tweezers sorted that out.
I want to print out PowerPoint slides with the notes under each one, but I want more than one slide per page, which is the only PPT option.
Here are the steps I used.
(1) ‘Designed’ notes text in PPT; something like Univers 12 pt for notes and 9 pt for refs/sources. Formatted notes consistently.
To work with the slide notes in the text block under the slide, used ‘Notes Page’ under View. Can resize and so on and get WYSIWYG while formatting.
(2) Used CutePDF to print to PDF file. Made sure paper was A4. Set to high DPI. Other settings in Printer Properties that might help if font issues arise are arrowed in green in the image.
The Print settings for PowerPoint (rather than the printer) were:
- Color (sic)
- Notes Page (Print slides with notes)
- Print all slides (or the range you want)
- Printer: CutePDF
- No header or footer
Then printed and saved the file.
(3) Used pdfcrop.sh in Cygwin:
$ pdfcrop.sh -t "40 100 40 100" infile.pdf outfile.pdf
(The four numbers are how much to crop from left, top, right, bottom; I worked them out by opening the PDF in GSview, which gives coordinates of the pointer.) I know there are graphical cropping tools, but this ‘just works’ and can do lots of pages.
Can also use Heiko Oberdiek’s pdfcrop:
$ pdfcrop --clip --margins "9 9 -80 -120" temp.pdf PDFCROP 1.38, 2012/11/02 - Copyright (c) 2002-2012 by Heiko Oberdiek. ==> 127 pages written on `temp-crop.pdf'.
In this case, set the margins to be added to the area that a tight crop of all white pixels would do if done automatically. That means I ended up adding a 9 bp margin top and left. The clip right and bottom was determined by the page number in the bottom right corner, so the -80 goes 80 in from the outside edge of the page number, and similar for the 120. It’s a bit messy but reviewing the results in gv and then iterating works well enough.
(4) Opened cropped file in Acrobat and printed to PDF again, also using CutePDF, again checking for A4 paper, this time landscape, Multiple 2×1.
In Cygwin, used something like
$ pdfnup --batch --suffix 'twoup' infile.pdf
Note that this gives different margins around the combined pages — pdfnup makes for bigger slides and less white space than Acrobat (note, I only have the reader, not Professional).
Installing a2ps on my Debian Linux box.
sudo apt-get install a2ps
and since I’d been printing from the GUI, had to define the default printer
$ lpstat -p -d printer Brother-HL-5350DN is idle. enabled since Thu 19 Apr 2018 20:31:20 AEST printer Stylus-TX100 is idle. enabled since Fri 06 Apr 2018 20:23:28 AEST $ lpoptions -d Brother-HL-5350DN
Then tested a file using a2ps and got this on the printed sheet:
ERROR NAME; undefined COMMAND; Helvetica-Bold OPERAND STACK;
which is not very helpful. Tried changing font by specifying a different prologue; same problem.
Can test by sending output to a file:
$ a2ps input.txt -o output.ps $ gv output.ps
Output to a file looks fine. So problem is that it is not a PostScript printer. Duh! Took me too long to twig, but I got there in the end. Plain text works fine — I can lp the file, for example, and get a good result.
So what to do?
$ info a2ps
and hunt around.
My printer is a PCL printer (printer command language, like most HP-clone ones) and a good reliable subset of PCL can be obtained by pretending it is a LaserJet 4 (ljet4 in GhostScript) (600 dpi is enough for this).
So, here is my a2ps config file:
$ cat .a2ps/a2psrc Options: --medium=A4 Options: --sides=2 Options: -2 Options: -d Brother-HL-5350DN Options: --prologue=fixed Printer: Brother-HL-5350DN \ | gs -q -dNOPAUSE -sDEVICE=ljet4 -sOutputFile=- - -c quit\ | lp -d Brother-HL-5350DN
And this gives me the output I wanted. I might need to add ‘tumble’.
This is really simple but what the hell, blog needs posts.
What are checksums? Basically, an algorithm creates some kind of code (string of characters) based on the bits and bytes in a file, and ideally the checksum is different if even a tiny change is made to the file.
So, for example, a website that hosts files might provide the file — say an iso disk image — plus a checksum (a string of characters). We download the file, which might be GB of data, then run the checksum program locally and if it matches the checksum the website posted, we know we downloaded the file successfully. It also has security aspects — if someone messes with the file but does not change the expected checksum, there will be a mismatch. Of course, if they compromise the file and then hack the website and change the posted checksum, all bets are off.
But how about a concrete example?
Let’s say I go to http://ftp.netbsd.org/pub/NetBSD/install-images/7.1.2/ and download an install disk for the AlphaServer that I bought off ebay for 99¢ (well, I paid $1).
So I download NetBSD-7.1.2-alpha.iso.
In the same directory on the server there are two files — MD5 and SHA512. I can look at those and I see:
MD5 (NetBSD-7.1.2-acorn26.iso) = 502dca7c8628b7583500ccf2436e6eba MD5 (NetBSD-7.1.2-acorn32.iso) = cd03d084925ee592d85603dd2334b390 MD5 (NetBSD-7.1.2-alpha.iso) = 090c25b2fcb7e770a6ae5b615a96963c MD5 (NetBSD-7.1.2-amd64-install.img.gz) = cbd76159c1ed5eb32a19a3b19eae8cfd MD5 (NetBSD-7.1.2-amd64.iso) = 2765516ec1b2ed56923c623e890388f0 MD5 (NetBSD-7.1.2-amiga.iso) = 35a345c82c9b399d1fc4ee6553849de8 MD5 (NetBSD-7.1.2-arc.iso) = cf2abd42a8e1244430dd0536c686d0b9 MD5 (NetBSD-7.1.2-atari.iso) = 2010fe541156c9650d2a2566e0ceb7a0
(the file goes down a long way — NetBSD runs on almost anything).
SHA512 (NetBSD-7.1.2-acorn26.iso) = 533ae5b61f7e9a870dacdb3a4e57df8cc768f93d5cdda7407dcecbe42dbb9856421bbb73eacbad66d08e61498385b5b3571fa3d66c66afb8eef07a27600d603d SHA512 (NetBSD-7.1.2-acorn32.iso) = 0367108ec724ca47609fa324c9d1012e43c8249978afd057d9410e5724307309e3e8899167f6b1f58816c232a7ee7dc64aa93acaf7940b7384ae177bedf0af1a SHA512 (NetBSD-7.1.2-alpha.iso) = dce2431b41f656bd07baffb8b97a270e32261600231f631761ccbeeefb8c8fd437ff02ed5ed2253699f14aebc45bc79d7633c2bb8874b8d24596cd43b7b537fc SHA512 (NetBSD-7.1.2-amd64-install.img.gz) = 3e625cd6335c9bba631e5aee7c40a4606b915b3d73aeeaba1b693c4d9a7ad627d1a3ac08b23144fa5f1e2b84c9fc4cd8faef2d4a681a79862f3b8c29c103b85c SHA512 (NetBSD-7.1.2-amd64.iso) = aaccacbfa3ee5a497170025aed9426de1ef91f8f7ebdaf862bd178c4922a5db1b82171832c916acd7a4e2038dd9ec39ef1061c41d98c5b5af56e3165cc945539
where we can see that the SHA512 sums are longer and generally considered ‘better’.
So I’ve got the file on my Linux box. I just do the sums:
$ md5sum NetBSD-7.1.2-alpha.iso 090c25b2fcb7e770a6ae5b615a96963c NetBSD-7.1.2-alpha.iso $ sha512sum NetBSD-7.1.2-alpha.iso dce2431b41f656bd07baffb8b97a270e32261600231f631761ccbeeefb8c8fd437ff02ed5ed2253699f14aebc45bc79d7633c2bb8874b8d24596cd43b7b537fc NetBSD-7.1.2-alpha.iso
And I can eyeball these and compare and see that all looks fine.
There’s another thing to do.
I can create little files with the same format as the output from the checksum programs, but using the values from the server’s files. Say I make md5.txt and it has a single line in it that looks like this:
I can then do this:
$ md5sum -c md5.txt NetBSD-7.1.2-alpha.iso: OK
and the checksum program will compare the strings for me. SHA does the same.
In my case, I am trying to get an OS to work on a badly mistreated DEC AlphaServer 1200, largely for the hell of it. The CD drives are old and may not be reliable, so it is really valuable to be able to eliminate one source of failure from the checks I have to do.