Home Computing

Computers

At present I own the following computers:

Currently in use

  1. An Intel i5-2500 quad-core desktop with 8 GB of memory, DVD, external SATA and USB 3.0 connections. There are three disks; a 250GB SSD as system disk, a 500GB Western Digital magnetic disk, and a second 250GB SSD which is used entirely used for Virtualbox images. The home directory on the system SSD is mirrored onto the 500GB disk every night by a cron job. There is also an external disk caddy connected by a USB 3.0 cable with a second 500 GB disk.

    There is a single monitor, a 23 inch LG with 1920*1080 resolution, shared beteween this machine and the Pentium 4 by a KVM switch.

  2. A Lenovo Thinkcenter, with 4GB of memory and a 250GB SSD. There is also, on the shelf, a 500GB disk with a validly-licensed copy of Windows 7. I only use it once a year to update my Garmin GPS unit for the car. I can't find any other uses for Windows 7.
  3. An ancient Toshiba Satellite; a 32-bit machine with 3 GB of usable memory. I put in a 100 GB SSD, and installed Peppermint Linux, which is a distribution suited for low-power machines. It works well as a spare machine that I can use for giving the occasional presentation. The battery is totally dead, so it needs mains power whenever it is in use. I also installed a wireless mouse, as the trackpad is unusable, to me at any rate. Since the machine cost me a few beers from a friend, it is great value.
  4. A Samsung Tab2 tablet, which gets a great deal of use.

No longer in use and in most cases gone the the great computer morgue in the sky

  1. A Pentium 4 1.8 MHz, with 512Mb of memory and an 80 GB disk. It has a DVD writer, a 10/100 Ethernet card, and a hardware modem that I have never used. I have recently equipped both this machine and the next one with hard disk caddies, making it much easier to use different disks with different operating systems. I strongly prefer this approach over multi-boot systems, as there is no risk of damaging more than one OS at a time.
    I currently have disks with Ubuntu Hardy Heron, which I use as my "production" system, a Windows 2000 disk, and a copy of FreeBSD 6.3. There are also several other older IDE disks, with all sorts of old stuff on them - such as a bootable copy of Caldera Unix for a 486, from before the time of the famous SCO lawsuit.
  2. A Pentium 120 that I have had since 1997, with 128 MB of memory and two 10 GB disks. It too has a disk caddy, and I have an almost-never-used Windows 95 configuration for it on a 1.7 GB disk. It also has a CD-RW writer, a hardware modem and an Ethernet card. The CPU fan failed some time ago, and I didn't notice. So it now reports its speed as 100 MHz; it has presumably got a little old and tired. But it has been extremely reliable for the whole of its life. In fact, I upgraded it from a 486 in 1997, so the power supply has been running since 1993, almost continuously. (The power supply looks pretty dusty, and I have cleaned out the vents to some extent, but I expect it will fail before very long.)

    It has now been taken out of service, and sits lonely and unused in the basement.
    For a while I used it as a web server, using Apache. One minor innovation is a CGI script, in Perl, which generates a set of index pages for my collection of digital photographs. With this, I have only to save a new photograph in the appropriate directory, and it will appear automatically in the index page for that collection.

  3. A 486DX-33, with 20 MB of memory, and a 500 MB disk. It ran an early version of Linux (Caldera 2.0 from memory), and had an Ethernet card and a modem. I got this machine from my sister-in-law, who said it was completely dead, and so she would not accept any money for it. She was quite right - it was as dead as a doornail, with a failed power supply. A used replacement later, and it was up and running Windows 3.1, to my pleasant surprise. I later installed Linux; a version by Caldera, I am sorry to report. It ran without interruption for over three years, until the power outage that disrupted life in Ottawa in August 2003. It has been running off and on since then, and never crashes. It was taken out of service when we moved house in 2006, but still sits in my basement ready for use in an 'emergency'. (What kind of emergency would need a 486 I can no longer imagine).
  4. An Asus Eee 701 netbook, which I bought in March 2008. It has a wireless connection, and I used it in other parts of the house, and in hotel rooms when we were traveling. It runs a customized version of Linux, and is very compact and portable. The battery life is very short, and it has a serious problem with screen flickering, so it must be counted as deceased. It has effectively been replaced by tablets; first a Nexus 10, and now a Samsung SM T318.

Networking

The i5 and the Thinkcenter are networked together, using Ethernet and a wireless router, which isolates my home network from the outside world. The high-speed connection from our local cable service comes in to the router, which provides Network Address Translation, and gives me some confidence that hackers will have a relatively hard time. I could improve the protection with a little more work - one of the many things on my "to-do" list.

Getting the networking to do what I want has been more challenging than I expected. It proved quite easy to get to the stage where I could "ping" each machine from the other, but I had a learning curve to climb before I was able to share directories across the network using NFS, and to be able to telnet and ftp between them. It all came down to getting the configuration files right, and now I know how to do it, it seems easy.

I run Samba, which enables a FreeBSD or Linux machine to "pretend" to be an Windows NT server, so that it can serve files to Windows clients. This enables me to access my Linux home directory from a Windows machine - even from a Windows machine running under VirtualBox.

Backing up

As it is now

I have three spare 500 GB disks that can be mounted in a USB socket, and I do a full backup every night at 3:00 am. I rotate the disks every few days, and keep one hidden away that is update less frequently.

I also copy everything of value to the Amazon S3 service, which provides very inexpensive storage that is 'off-site'. This backup is done once each week. I have copies of very critical files, such as the Amazon S3 keys, ssh keys and passwords, all encrypted, in several places, including a USB memory stick that stays with me at all times.

As it was years ago

Now everything is set up the way I want, and seems to work very reliably. I use the Pentium 4 as a backup machine, and the home directories from the other machines are backed up automatically each night. Every month, I copy the contents of these backups to a CD or DVD, so I have a reliable record of all useful files that were on each machine, using a recording medium that cannot be affected by power surges or other electrical failures. I keep backup copies of the most critical CDs at an "off-site location" - that is, not in my home. Any files which are not in the home directory, and which I have modified, are copied to a place in the home directory structure just before the backup is made. This includes the many configuration files such as those in /etc. My method here is simple. I include a comment with my initials in any file I modify, and these are picked up automatically by the backup script, using grep. I am thus quite confident that I can reconstruct the state of a machine in an hour or two, even if its filesystems are completely destroyed. And yes - I have practiced this.

I also have several flash memory drives, that connect to a USB port. These are excellent value for money, and are getting cheaper by the month. I bought a 128MB flash drive for $29 from Staples, and reformatted it as a UFS device, and it is used for an additional nightly backup of selected files from my home directory. I have another which lives on my keychain, and holds encrypted backups of a handful of files that I consider most valuable. These drives are now getting so cheap that I may replace it with an 8GB drive which will hold everything I value, including photos (but not movies).

IOmega ZIP drive

I owned one of the early Iomega Zip drives (the 100MB version) for several years, and with help from a FreeBSD committer was one of the first people to use one with FreeBSD. Despite the frequent "click of death" problems, mine functioned perfectly for several years, with never a dropped byte. I recently moved it from the Pentium 120 to the Pentium 1.8 GHz, and it lasted a week or two before dying of "click of death". So it may, as rumoured, have something to do with the power supply characteristics. It is not worth replacing, and I have long ago copied anything of value to CDs. So - ZIP-RIP!
Last updated : 2020-07-09