CD-ROM and Linux
To mount a CD-ROM, insert it in the drive and use the mount command (as root). A typical command line is the following:
% mount -t iso9660 -r /dev/cdrom /mnt
The example above assumes that the CD-ROM device file is /dev/cdrom and the disc is ISO-9660 formatted (this is almost always the case). The -r option indicates that the disc is to be mounted read-only. If successful, the CD can now be accessed under the directory /mnt.
For a more permanent setup, you may wish to mount the CD under a more meaningful name such as /cdrom. By adding an entry to the /etc/fstab file you can have a CD-ROM automatically mounted when Linux boots; see the fstab(5) man page for details.
When finished with the CD, it can be unmounted using the umount command (again, run this as root):
% umount /mnt
If you want to allow non-root users to mount and unmount CD-ROMs, you can use the “user” option provided by some mount commands. If you make an entry such as the following in /etc/fstab:
/dev/sbpcd /cdrom iso9660 user,noauto,ro
then an ordinary user will be permitted to mount and unmount the drive using these commands:
% mount /cdrom % umount /cdrom
The disc will be mounted with some options that help ensure security (e.g., programs on the CD cannot be executed and device files are ignored). Another method is to obtain or write a program such as usermount which runs setuid to root and allows restricted mounting of specific devices (e.g., CD-ROM and floppies) for non-root users.
PhotoCDs use an ISO-9660 file system to store image files in a proprietary format, at several different resolutions. Not all CD-ROM drives support reading PhotoCDs. If yours does, you can mount it and use a program such as hpcdtoppm to convert the files to a format that can be displayed using graphics file viewers such as xloadimage or xv.
The hpcdtoppm program is part of the PBM (portable bit map) utilities, available on many Internet archive sites (look for pbm or netpbm).
The program xpcd is an X11-based utility for manipulating PhotoCD images. You can select the images with a mouse, preview them in a small window, and load the image with any of the five possible resolutions. You can also mark a part of the image and load only the selected part. This program can be found at ftp.cs.tu-berlin.de in the file /pub/linux/Local/misc/ xpcd-0.2.tar.gz.
Several programs are available that allow playing audio CDs, either through a headphone jack or an attached sound card. workman, supplied with many Linux distributions, is one such program. It sports a graphical user interface that resembles the controls provided on audio CD players. Simple command-line CD player programs also exist. Note that to play an audio CD you should not try to mount it.
The CD player programs simply route the analog output of the drive to an external device. Some CD-ROM drives also support reading the digital sound data contained on audio CDs. Using a program such as cdda2wav you can save audio tracks from a CD-ROM as a sound file (e.g., in .wav format).
The Inheriting File System (IFS) is a kernel driver that allows mounting multiple file systems at the same point. By mounting a hard disk directory over a CD-ROM file system, you can effectively obtain a writable CD-ROM file system.
At the time of this writing, an experimental version of IFS, written by Werner Almesberger for the 0.99 Linux kernel, is available as a kernel patch.
If you want to create your own CD-ROM, either by using a writable CD drive or sending a tape to a vendor to be mastered, there are some tools available under Linux that you can use.
The mkisofs package allows creating an ISO-9660 file system on a disk partition. This can be used to assist in creating and testing CD-ROM file systems before mastering discs.
There are also some utilities available for verifying the format of ISO-9660 file systems; these can be useful for checking suspect CD-ROMs.
Practical Task Scheduling Deployment
July 20, 2016 12:00 pm CDT
One of the best things about the UNIX environment (aside from being stable and efficient) is the vast array of software tools available to help you do your job. Traditionally, a UNIX tool does only one thing, but does that one thing very well. For example, grep is very easy to use and can search vast amounts of data quickly. The find tool can find a particular file or files based on all kinds of criteria. It's pretty easy to string these tools together to build even more powerful tools, such as a tool that finds all of the .log files in the /home directory and searches each one for a particular entry. This erector-set mentality allows UNIX system administrators to seem to always have the right tool for the job.
Cron traditionally has been considered another such a tool for job scheduling, but is it enough? This webinar considers that very question. The first part builds on a previous Geek Guide, Beyond Cron, and briefly describes how to know when it might be time to consider upgrading your job scheduling infrastructure. The second part presents an actual planning and implementation framework.
Join Linux Journal's Mike Diehl and Pat Cameron of Help Systems.
Free to Linux Journal readers.Register Now!
- SUSE LLC's SUSE Manager
- Murat Yener and Onur Dundar's Expert Android Studio (Wrox)
- My +1 Sword of Productivity
- Managing Linux Using Puppet
- Non-Linux FOSS: Caffeine!
- Doing for User Space What We Did for Kernel Space
- SuperTuxKart 0.9.2 Released
- Google's SwiftShader Released
- Parsing an RSS News Feed with a Bash Script
- Rogue Wave Software's Zend Server
With all the industry talk about the benefits of Linux on Power and all the performance advantages offered by its open architecture, you may be considering a move in that direction. If you are thinking about analytics, big data and cloud computing, you would be right to evaluate Power. The idea of using commodity x86 hardware and replacing it every three years is an outdated cost model. It doesn’t consider the total cost of ownership, and it doesn’t consider the advantage of real processing power, high-availability and multithreading like a demon.
This ebook takes a look at some of the practical applications of the Linux on Power platform and ways you might bring all the performance power of this open architecture to bear for your organization. There are no smoke and mirrors here—just hard, cold, empirical evidence provided by independent sources. I also consider some innovative ways Linux on Power will be used in the future.Get the Guide