Category: Linux

Linux and the Open Source Lifestyle

Fedora Docs Directly in your Electronic Reader

by

Publican, which is the software that generates Fedora Documentation, now supports OPDS, the Open Publication Distribution System. OPDS is a syndication format for electronic publications. Thus, Electronic Reader programs or devices can be given a URL for the Fedora Docs catalog, and can browse through it, and download publications for reading.

If you have a program that supports OPDS, add in the URL http://docs.fedoraproject.org/opds.xml, or if you want our preference…US-English, try http://docs.fedoraproject.org/en-US/opds.xml.

We use Aldiko,  an ebook book reader for the Android mobile OS. But there are several more. For a list of some complaint readers, click here.

Related articles by Zemanta

Some CableCard Content Will Be Available to Linux

by

CableLabs, the independent consortium of cable operators which creates specifications for cable television compatible products has approved two measures that will permit Home Theater PCs running Linux to take advantage of some U.S. cable television content.

Cable providers can set copy control information for their content to specify how the content can be duplicated, setting it to Copy Once, Copy Never, or Copy Freely. In the United States, the Federal Communications Commission, or FCC, specified that all broadcast television channels must be set as Copy Freely. Non-premium subscription programming has to be set to at least Copy Once, but of course can be set to Copy Freely. This is where cable providers vary, as some tend to set all programs as Copy Once and others tend to set all programs as Copy Freely.

CableLabs has approved the passing of content coded as Copy Free without Digital Rights Management, or DRM. DRM allows a content provider to restrict what you can do with content once downloaded or recorded. No current Linux based software has licensed or been approved to carry content with DRM, and the decision by CableLabs means that users of MythTV, will be able to decrypt and record some content. CableLabs is charged with approving all CableCard compatible devices.

A CableCard is a PCMCIA card which a carrier is legally obligated to offer on request, which can be added to a tuner to decrypt content. However, until recently, PC CableCard peripherals were extremely limited. Two manufacturers have worked hard to open up the PC market to this hardware and have advocated for Linux support. Ceton, just recently launched its InfiniTV4 PCI-Express card, and Silicondust, creators of the popular and Linux compatible HDHomerun networked digital tuner are set to release a cablecard enabled version later this year.  Jeremy Hammer, VP of Systems integration for Ceton, and a Fedora user, advised that the Ceton product will fully support Linux and MythTV to the extent they are able.

Unfortunately for us, our service provider, Time Warner Cable, sets nearly everything to Copy Once, this rendering the device pretty much useless unless they change their ways. Comcast, however, apparently is much more open(surprising, isn’t it?), setting most of its non-premium content to Copy Freely. Being as you need to rent the cable card from the cable company anyway, we do not see the point of restricted content they know you’ve paid for.

However, we’ve never quite gotten the point of DRM in general. It more often restricts legitimate usage over actually stopping piracy. And as we’ve been reminded recently, fair use for recorded content is not to keep it on your hard drive forever. If you really like something enough to keep, you probably should buy it. You’ll get a better quality version…and if you’re lucky…extras.

Simple Power Management Under Fedora

by
SATA-Kabeladapter
Image via Wikipedia

This post is a result of experimentation, but also of some information from the RHEL6 Power Management Guide. Most people tend to ignore power management, but remember, power management can result in lower utility bills as well as increased life of components.

First, turn on CPUSpeed if it isn’t on. It may require enabling BIOS settings. Look for names like SpeedStep, Cool’n’Quiet, PowerNow!, ACPI, SMART to enable in BIOS. Then, set CPUSpeed to run. CPUSpeed dynamically adjusts the speed and voltage of the CPU based on demand.

While you’re in BIOS, take the opportunity to disable any system piece you aren’t using. For example, your parallel port.

Tuned is a daemon that monitors the use of system components and dynamically tunes system settings based on that monitoring information. A detailed system configuration might be too time-consuming for most. Most people will not do certain things unless it is easy and does not inconvenience them too much. Thus, tuned comes with preset profiles.

Active-State Power Management (ASPM) saves power in the Peripheral Component Interconnect Express (PCI Express or PCIe) subsystem by setting a lower power state for PCIe links when the devices to which they connect are not in use. ASPM controls the power state at both ends of the link, and saves power in the link even when the device at the end of the link is in a fully powered-on state.

Aggressive Link Power Management (ALPM) is a power-saving technique that helps the disk save power by setting a SATA link to the disk to a low-power setting during idle time (that is when there is no I/O). ALPM automatically sets the SATA link back to an active power state once I/O requests are queued to that link.

tuned has the following profiles:

  • default – lowest impact on power savings, only enables CPU and Disk Power Savings
  • desktop-powersave – designed for desktops. Enables CPU, Disk, and Ethernet savings, as well as ALPM power saving for SATA.
  • server-powersave – Designed for Servers. Enables ALPM powersaving for SATA host adapters, disables CD-ROM polling through HAL (refer to the hal-disable-polling man page) as well as the CPU and disk power controls.
  • laptop-ac-powersave – medium-impact profile for laptops on AC. Enables CPU, ethernet, disk, wi-fi, and ALPM power saving for SATA.
  • laptop-battery-powersave – high-impact profile for laptops on battery. All the same from the AC-powersave, plus multi-core power-savings
    scheduler for low wakeup systems and makes sure that the ondemand governor is active and that AC97 audio power-saving is enabled. Will work for any system, not just a laptop, there will be a noticeable impact on performance.
  • throughput-performance – server profile for throughput performance. Disables power saving mechanisms and enables sysctl settings that improve the throughput performance of your disk and network I/O, and switches to the deadline scheduler
  • latency-performance – server profile for typical latency performance tuning. It disables power saving mechanisms and enables sysctl settings that improve the latency performance of your network I/O.

To list available profiles,  use the command tuned-adm list.

To switch to another profile, use tuned-adm profile profile_name.

Reducing the amount of work performed by the hardware is the best way to save power. Applications that request unnecessary work prevent hardware from entering a reduced state. Fedora has already done a lot of work in reducing unnecessary processes, but it can’t do everything. Audit running processes and discontinue anything unnecessary.

But, let’s address one concern. By turning things off or slowing them down, it means you may have a few seconds wait while they reactivate. That may be a downside, but the secret is to find a balance between always on and always off. It is better to turn it on than leave it off. Plan well early on.

We’ll have more on this later.

Related articles by Zemanta

SouthEast Linux Fest is Over

by

This weekend, our Editor was down at the SouthEast Linux Fest in South Carolina. Three fun filled days of interacting, speakers, vendors, free stuff, and oddly enough, playing board games. The panels put a lot of interesting thoughts on the table, and over the coming weeks, we plan to discuss a few of them.

These sort of discussions always light a fire under us. Already, we’ve started hardening our servers in various ways, started looking at a new way to explain MythTV to the guys over at HTPCentric, got scared about IPV6, etc.

SELF’s speakers were all filmed, and the video will be available eventually. We’ll post links when available.

Related articles by Zemanta

Planning for and Optimizing Solid State Drives

by

This past week, we installed our first Solid State Drive. We had a lot of concern about this technology early on. There were reports of gradual performance degradation.This has been improved, however, and we’ll discuss some ways to better optimize your experience. Hopefully, in future Linux releases some of these options will be configured automatically

The biggest development that has been made to preserve longevity on these drives is TRIM. The TRIM command allows the operating system to inform the drive which data blocks are no longer in use and can be wiped. TRIM is supported beginning in kernel 2.6.33 and can be enabled under Linux by editing the mount options to include the discard option, such as in the below example.

/dev/sda1 / ext4 discard,defaults

Other suggestions include removing journaling and limiting read and writes to the drive. This will extend life as well, but without journaling, there is some risk of data loss in the event of a crash. However, Theodore Tso debunked this thought last year in a blog post, in which he concluded that the overhead is minimal.

  • Another Linux-based tuning technique is to disable Linux from writing the last accessed time to files. This can be done by adding noatime to the above command. Realistically, on many computers the last accessed time is not extremely important. Do not confuse accessed time with the last modified time.
  • Add the option elevator=deadline to your grub boot configuration to use the deadline disk scheduler. If you have a slower CPU go for the noop scheduler. The default schedulers are optimized for traditional hard drives.
  • Move your Firefox Cache to RAM – Open Firefox and enter about:config in the location bar.  Right-click and choose the option New->String.  Enter “browser.cache.disk.parent_directory” for the preference name, and for the string value enter “/dev/shm/”. That will also reduce writes and improve performance.
  • Reduce kernel swappiness(the tendency for the OS to swap from physical memory to a hard drive based swap file). Add vm.swappiness  = ? to /etc/sysctl.conf. Default is 60, out of 0-100. Some suggest lowering it all the way to 0. Experiment with what works for you. This suggestion is not limited to systems with SSDs.

Bear in mind for the Firefox and Swappiness suggestions, you should have enough RAM to support reducing the swap and moving the cache to memory.

Now that we’ve covered optimizing the solid state drive, let’s discuss usage. We used the Kingston 30GB SSD, reviewed here in comparison to the Intel value SSD, which we also considered. The SSD, because of price and size considerations, is not ideal for all functions. You can see a picture of it just before install in the laptop we used to write this blog entry above.

SSDs are small in size, but speedy. Their best use is as an operating system drive. In our first test case, which is a laptop, they are the only drive. However, the laptop is mostly OS only. All media and other files are stored on a file server. With this drive, the laptop flies along and is extremely quiet as an SSD makes no noise. We have not done any battery life tests, but there is some evidence from those who have that some SSDs may be less energy efficient than conventional hard drives.

In conclusion, with the price of SSDs continuing to drop, it is a good time to start considering it as a boot/OS drive for your systems. Now that we’ve grown comfortable with its usage, we plan on expanding it to future renovations, including in our file server.

Update(06/03/10): The day after we wrote this, AnandTech released a review of three SSDs, including our Kingston 30GB as well as the Onyx and Intel budget SSDs. Certainly makes us feel better about our purchase.

MythTV 0.23 Release Candidate 1 Released

by
Watch Recordings Menu under Graphite theme

Today, the MythTV Development team released the first release candidate for MythTV version 0.23. Highlights include:

  • Beta of MythNetVision, which we previously reported on. MythNetVision is a an official Internet video plugin being developed for MythTV. It uses user contributed scripts scripts to parse information so that it can be extended to additional sites as time goes by. When possible, it will download the video to the drive. Otherwise it will launch a browser(MythBrowser or otherwise) to view it.
  • Rewritten Audio System
  • A New Event System to trigger user specified actions when certain events occur in MythTV.

Looks good so far. We’ve been waiting for MythNetVision, and a lot of the fixes set to come with future versions. The best news is the more rapid release cycle. The gap between 0.21 and 0.22 was much longer than anyone preferred. Hoping to see more.

Bad Luck Comes in Threes – Detecting Hardware Failure

by
A set of 4 industry standard 80mm fans, most c...
Image via Wikipedia

It would be very easy if we could blame Geektonic for this. After he featured a MythTV system, we agreed to offer him a profile of our primary MythTV setup. It seemed like a good time to dust the system both inside and out, in preparation for some fresh photos.

We have a dedicated MythTV backend which doubles as a file server. We exercise basic power saving functions on it, including CPU frequency scaling. We discovered some hardware problems during the cleaning process.

There was an odd grinding noise that gradually appeared. Originally, we attributed it to a cable hitting against one of the case fans, but there was no such cable. We used velcro cable ties to bundle our cables together just in case. The server scales the CPU to its normal specs only when it is under load. We’d been having crashes whenever we tried any video transcoding. Finally, we tied these two problems we thought unrelated together. The fan was failing, and could handle cooling, but not when the computer went full throttle, during which it gradually overheated till the built-in BIOS shutdown temperature is reached.

So we ran to the store the next day, bought a new CPU fan, and replaced ours. We’re always nervous about pulling off a long-running CPU fan, as the thermal paste used between the heatsink and the processor can tend to act, as the name paste implies, as a bond that could cause damage if you are not very careful in pulling it up. But there were no problems, and the CPU temperatures returned to normal.

Then, today, half a week later, we received notification of prefailure on one of the drives. As we speak, we’re moving data off of it. It will be removed, lashed to a different system, and a manufacturer low-level test mechanism used to check the drive. Either way, it is still under warranty and could be exchanged for replacement by the manufacturer.

It is said bad luck comes in threes, so we thought this was a perfect time to discuss how you can monitor and protect yourself from hardware failure. We’ll focus on these techniques for Linux users, but the idea applies to all systems.

  • S.M.A.R.T.(Self Monitoring, Analysis, and Reporting Tool) -  A system built into every hard drive that monitors several variables to predict drive failure before it happens.
  • Temperature/Fan – There are temperature and fan speed sensors in motherboards that permit monitoring of computers for overheating.

Here are, in our opinion, two very important things you need to enable if you are going to protect your computer. But should be enabled in the motherboard BIOS to start. If your BIOS has a shutdown temperature option, that if reached, will turn the computer off…enable it. Enable SMART reporting as well.

Smartmontools is available in all Linux distributions. Make sure it, or another SMART monitoring tool is enabled and configured to send you an alert if it detects anything. Smartmontools on one of our systems was configured to send an email to the root email account, which was local to the system, and rarely used. Make sure it is sent somewhere you will see it.

For temperature and fans, the standard is LM_Sensors, which may tae some tweaing. Check your estimated CPU temperature in BIOS, then boot and compare it to the one in lm_sensors. If they don’t match, you may need to tweak your settings. Make sure this also generates an alert when it reaches a threshold so you can take action.

We’re a bit mystified as to why features like this aren’t built into Windows, but many manufacturers do offer their own monitoring utilities you can install to monitor vitals. Either way, by setting up your computer early on monitor for these things, you can head off some catastrophic failure. Barring that…backup often.

Blu-Ray on Linux – Part 2

by
Blu-Ray Disc logo
Image via Wikipedia

After a lot of consideration between a dedicated hardware blu-ray player and a blu-ray drive, we prepared to take advantage of Newegg’s $49.99 Blu-Ray drive.

At the last minute, we changed to a $129.99 Blu-Ray burner, so we can experiment with blu-ray burning as well as play-back under Linux.

We installed it in a secondary computer, as opposed to our production system, and installed the MakeMKV beta for Linux. It compiled without incident, and was able to rip our test Blu-Ray video to a test drive.

Now, we want to emphasize this very clearly. WE HAVE NO INTENTION OF DISTRIBUTING ANY ILLEGAL VIDEO. Our intention is to be able to exercise our fair use and playback our legally purchased or legally rented videos.

It is a pain in the butt to have to spend this time ripping the Blu-Ray before we can play it. But that is the price we pay for our open-source lifestyle choice.

We figure, for our legally owned(not rented) Blu-Rays, we have two options.

  1. Rip the Blu-Ray, watch it, then delete the working files. This seems to make sense, as a single movie rip is taking up 30GB on a drive. How many of those is it worth storing.
  2. Do above, but create a lower-quality archival copy that can fit on a single DVD. Our first blu-ray came with a digital copy on a separate DVD that can only be played under Windows, so we might as well discard that disc and replace it with our on archival DVD.

Either of these, again, involve a fair amount of preprocessing and working space, however. In the meantime, however, we have a new movie to watch.

Related articles by Zemanta

Blu-Ray and Linux – Or Why We Don’t Have Blu-Ray Yet

by
Blu-ray Disc
Image via Wikipedia

Many years ago, we owned a hardware DVD player. Then, over time, we dropped the extra device in favor of playing movies back through our Home Theater PC.

But Blu-Ray is a bit more complicated. We use Linux, and a group of intrepid individuals reverse-engineered the DVD standard, as no one would offer a licensed copy. At least until this past July, when Fluendo released a licensed DVD player for Linux. They have not yet released a Blu-Ray player.

Which leaves the reverse-engineering road. The latest versions of mplayer now support most of the Blu-Ray codecs. But that isn’t playback of the disc. That means you still need to rip and encode the disc for it to work. Which is where the problem comes in. There is a limited guide available for Ubuntu that offers some updates on what you might do.

MakeMKV has a Linux version, which apparently works for ripping Blu-Ray discs, even many BD+ encrypted titles. It will take them directly to the Matroska(MKV) container format.

A Blu-Ray rip will take at least 50GB, before post-processing down to a smaller format, which is a lot of hard drive space. Especially if your goal is to merely watch the disc.

Am looking forward to testing all of these methods someday, but will need a Blu-Ray drive and a sample Blu-Ray disc. Will likely choose to wait. Although we may choose to try a hardware Blu-Ray player to dip our feet into the world of Blu-Rays. We don’t really need to watch HD movies, as much as it would enhance our experience, but we want to slowly phase out purchasing DVDs in favor of Blu-Ray for new releases. Not that we buy any movies regularly. We save purchases for special titles.

We’d like to hear what other people think on the subject.

LightScribing and Fedora

by
A LightScribe disc label printed with Wikipedi...
Image via Wikipedia

LightScribe is nothing new.  It has been around for years, We like the idea. After all, no one can read our handwriting anyway. And we want something that looks nice, but it easy to generate. A simple label making program that allows us to type the information and have it burned to the top of the DVD or CD seems ideal.

There are problems though. Lightscribe discs shouldn’t be stored in direct sunlight. It is recommended they be stored in polypropylene disc sleeves rather than PVC sleeves, and even certain residual chemicals on your hands can cause discloration.

For the record, the same technology, but not compatible, is available in the competing standard of  LabelFlash, which has some of the same problems. Neither of them offer color…yet.

The surprising thing is that this technology isn’t more prevalent. Of course, there is pricing to consider. We went to discounter Meritline.com to check on pricing. A 25 pack of Philips Lightscribe DVD+Rs costs $7.99, or about 32 cents a DVD. A 50 pack of regular Philips DVD+Rs costs $15.50, or about 31 cents a DVD. We picked Philips because they are about average quality. Either way, going Lightscribe isn’t going to break the bank.

Even with that, you can get DVDs for less if you look around. Our last DVD purchase was 100 Sony DVDs at 20 cents a DVD during a Staples sale. We hand label such things. But we keep a spindle of lightscribe CDs and DVDs, and do burn them occasionally.

What prompts us thinking about this again? Fedora has released a complete set of Lightscribe labels. They’ve produced LightScribe versions before, but this is the first time they’ve generated versions of all their labels, regular and Lightscribe, for all of the release versions, the various Live Disks and the Installation DVDs, as well as the blank label so you can add your own text.

Their label isn’t ideal for Lightscribe, which needs high contrast, but they’ve made the effort, and even without the background, the text and Fedora bubble logo made our burn look professional. We will have our Fedora review coming up soon, but we’ve had some trouble with it on our netbook, the first system to receive the upgrade, and want to fiddle a bit before getting to a second computer.