I am well aware that this list is free and voluntary and that no one is under any obligation to solve my problems so please don't think that I am unhappy with the people in this list. As I have said in other posts, I would really like to be able to leave the Gates world but so far this has not been possible. Still I am running into a lot of little problems that keep me going to Windows to get certain tasks done because I still can't solve these problems with SuSE. I think a lot of my problems are permission related but I can't solve them without a little help. With a little detective work I was able to find from fstab and Konqueror file manager all the relationships between CD drives and names. From Konqueror I find that /cdrom is a link to /media/cdrom. fstab shows me that /media/cdrom is a mount point for /dev/cdrom and Konqueror shows me that /dev/cdrom is a link to /dev/sr0. Great, now I have the chain but what do I do with this in order to get grip to work for a normal (not root) user? What permissions must be set? Why does the IDE DVD drive work with no adjustments while the SCSI CD-RW not work for a normal user but does work for root. Is it possibly the SCSI controller that needs permission adjustment? If so, how do I find what is the /dev and what permission must be set? [rant on] The really frustrating thing is that though I believe some of these problems to be simple ones, I get zero response. Also I find that these issues are VERY common but information scarce or incomplete. I feel that the Linux community is too secretive at times. Why do I see very long threads about disk polishing or YaST 1 vs YaST 2 but zero answers to what I believe are simple questions about devices? Why is it so often I see in FAQs or posts that critical details are omitted? Sometimes I have seen over time that there are many posts on a subject that could be answered if a FAQ contained sufficient information for the reader to be able to solve his problems. A good example is CD ripping. There is a FAQ at http://dinamizm.ath.cx/articles/cdrip.html that covers the subject but has several errors and is also lacking information that could help the reader to deal with exceptions. According to the SuSE 8.0 manual and posts in this list, typing audiocd:/ in Konqueror will let me rip CDs but neither the SuSE book or the posts have bothered to mention prerequisites that would allow this to work. Another great example is something really simple: symbolic links. I could find information in "Running Linux" (O'Reilly?) on creating a symbolic link but the writer didn't bother to mention how to get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link? [rant off] Damon Register
On Monday 16 December 2002 15.40, Damon Register wrote:
I think a lot of my problems are permission related but I can't solve them without a little help. With a little detective work I was able to find from fstab and Konqueror file manager all the relationships between CD drives and names. From Konqueror I find that /cdrom is a link to /media/cdrom. fstab shows me that /media/cdrom is a mount point for /dev/cdrom and Konqueror shows me that /dev/cdrom is a link to /dev/sr0. Great, now I have the chain but what do I do with this in order to get grip to work for a normal (not root) user? What permissions must be set?
Your regular user needs read and write permissions on sr0 and sg0, since most scsi tools use the SCSI generic interface (sg*) to work.
Why does the IDE DVD drive work with no adjustments while the SCSI CD-RW not work for a normal user but does work for root.
Bugs in SuSE's installer that messes up the permissions, perhaps? The ide-scsi setup seems to be the number 1 cause of problems lately. In future kernels we won't need it, thank $DEITY
[rant on] The really frustrating thing is that though I believe some of these problems to be simple ones, I get zero response.
I've answered questions like yours, about cd ripping, audio cd io slave in kde and cd burning about 2^15678 times. How many times do you think one can fruitfully answer the same question before breaking down into a sobbing wreck.
get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link?
A link is a file. You use rm to remove a file. The deductive leap isn't that large
On Monday 16 December 2002 06:01 am, Anders Johansson wrote:
get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link?
A link is a file. You use rm to remove a file. The deductive leap isn't that large
Say Anders...: How do I get rid of a member of a partitioned data set on my IBM 370 under MVS? Get my point? -- _________________________________________________ John Andersen / Juneau Alaska
On Monday 16 December 2002 21.36, John Andersen wrote:
On Monday 16 December 2002 06:01 am, Anders Johansson wrote:
get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link?
A link is a file. You use rm to remove a file. The deductive leap isn't that large
Say Anders...: How do I get rid of a member of a partitioned data set on my IBM 370 under MVS?
Having never worked directly with MVS I wouldn't know. I do know that IBM is pretty good with its interfaces, so it's probably a menu option. i vaguely remember seeing something in a roscoe menu, but it was too long ago, I can't be certain. If MVS commands anything like OS/400 it's probably something like wrkprtdtaset from the command prompt :)
Get my point?
Not really. Did you get mine? If the manual tells you that a symlink is just another file, and the section on files tells you that you remove files using 'rm', is it really necessary to repeat that piece of information in the section on symlinks? Are cross-references pedagogically bad?
On Monday 16 December 2002 11:52 am, Anders Johansson wrote:
On Monday 16 December 2002 21.36, John Andersen wrote:
On Monday 16 December 2002 06:01 am, Anders Johansson wrote:
get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link?
A link is a file. You use rm to remove a file. The deductive leap isn't that large
Say Anders...: How do I get rid of a member of a partitioned data set on my IBM 370 under MVS?
Having never worked directly with MVS I wouldn't know. I do know that IBM is pretty good with its interfaces, so it's probably a menu option. i vaguely remember seeing something in a roscoe menu, but it was too long ago, I can't be certain. If MVS commands anything like OS/400 it's probably something like wrkprtdtaset from the command prompt :)
Get my point?
Not really. Did you get mine?
If the manual tells you that a symlink is just another file, and the section on files tells you that you remove files using 'rm', is it really necessary to repeat that piece of information in the section on symlinks? Are cross-references pedagogically bad?
The point was that in a totally new computing environment it can be a big challange to figure out which is the proper manual to read let alone be able to draw inferances. (A PDS is something so basic to MVS that it is documented (extensivly) in some obscure manual which you may or may not have, but i've never seen it on any menu. The OP was obviously from a windows environment where Bill Gates just "invented" links last year, and therefore they can be quite mysterious. And thinking of a link as a file is NOT correct. Its just another pointer to a file, essentially another directory entry pointing to the file, and it acts quite differently than the actual file. (You can change permissions on a symbolic link till you are blue in the face and still achieve the desired results.) RMing the link may, or may not, remove the file, etc. The man pages for link, symlink, and ln, all sort of gloss over the removal aspect. In short it seems obvious to you and I, but its not unreasonable for a new linux user to be confused about this point. -- _________________________________________________ John Andersen / Juneau Alaska
On Monday 16 December 2002 22.33, John Andersen wrote:
The OP was obviously from a windows environment where Bill Gates just "invented" links last year, and therefore they can be quite mysterious.
I agree, they need to be documented. But windows has had shortcuts for a long time, and conceptually they're not that different. The details differ greatly, but ideas like "removing the link does not remove the file it points to" are there.
And thinking of a link as a file is NOT correct. Its just another pointer to a file, essentially another directory entry pointing to the file,
Not a symlink. A symlink has its own inode. A hard link is "just another directory entry" but a symlink is more. That's why you can have symlinks to files on other partitions but not hard links.
and it acts quite differently than the actual file. (You can change permissions on a symbolic link till you are blue in the face and still achieve the desired results.) RMing the link may, or may not, remove the file, etc.
Well, true, and that's what the manual entry for symlinks should focus on: what's different. Then it can refer to the general section on files for the basic stuff such as rm.
The man pages for link, symlink, and ln, all sort of gloss over the removal aspect.
In short it seems obvious to you and I, but its not unreasonable for a new linux user to be confused about this point.
I guess not. maybe manuals should emphasise the unix idea "everything is a file" more strongly?!
On Monday 16 December 2002 22:52, Anders Johansson wrote:
On Monday 16 December 2002 22.33, John Andersen wrote:
And thinking of a link as a file is NOT correct. Its just another pointer to a file, essentially another directory entry pointing to the file,
Not a symlink. A symlink has its own inode. A hard link is "just another directory entry" but a symlink is more. That's why you can have symlinks to files on other partitions but not hard links.
OK, so when 'should' we use a hardlink, and when 'should' we use a symlink? Dylan -- "Sweet moderation Heart of this nation Desert us not, we are Between the wars"
On Mon, 16 Dec 2002, Dylan wrote:
On Monday 16 December 2002 22:52, Anders Johansson wrote:
On Monday 16 December 2002 22.33, John Andersen wrote:
And thinking of a link as a file is NOT correct. Its just another pointer to a file, essentially another directory entry pointing to the file,
Not a symlink. A symlink has its own inode. A hard link is "just another directory entry" but a symlink is more. That's why you can have symlinks to files on other partitions but not hard links.
OK, so when 'should' we use a hardlink, and when 'should' we use a symlink?
For instance, if you want a shortcut to /var/log/messages, a hardlink would apparently cease to work when the logs are rotated, because suddenly your shortcut points to something like /var/log/messages-20021217.gz. This is because with a hardlink you are creating another reference to the same file, and this reference does not care if the original file gets renamed or moved or even deleted. If you want to point to a location (ie a filename) you should use a symlink. If you want to have the same file accessible for different users with different permissions, you have to use a hardlink. (If the file is a /dev/* entry, you could also just mknod with another name, because they only really care about the major/minor numbers and c or b type.) Symlinks can also point to items that don't exist in the filesystem. One example is the lock-file created by Mozilla, which is actually a symlink pointing to IPnumber:ProcessID. If you install a program in a non-standard location, it could be smart to put a symlink in one of the $PATH directories. If you used a hardlink, users would keep running the old version when you upgrade. So, to summarize: Unless you are trying to do something that requires a hardlink, just use symlinks. I hope this helped clear things up a bit. Regards Ole
On Monday 16 December 2002 02:45 pm, Ole Kofoed Hansen wrote:
This is because with a hardlink you are creating another reference to the same file, and this reference does not care if the original file gets renamed or moved or even deleted.
To beat this dead horse just a few more times..... ;-) With a hard link in place, the original file WILL NOT be deleted because as long as there is there is at least one link pointing to it the file is not deleted. It will not appear where it was originally located if you do rm upon its original name, but the hardlink will still be there and pointing to the exact same inode. Remember this when you are thinking of a way to prevent someone from deleting some critical file. A hardlink in another directory will prevent a delete, (but not necessarily a corruption of contents.) -- _________________________________________________ John Andersen / Juneau Alaska
Anders Johansson wrote: > > On Monday 16 December 2002 22.33, John Andersen wrote: > > Gates just "invented" links last year, and therefore they can be > > quite mysterious. Thanks Mr. Andersen for being more understanding of the difficulties encountered by the novice > greatly, but ideas like "removing the link does not remove the file it points > to" are there. but it doesn't do a lot of good to the novice if that information that is there is not so obvious. I read about links in "Running Linux" but it left me to wonder if deleting a link would delete the file and I didn't want to do that. > Well, true, and that's what the manual entry for symlinks should focus on: > what's different. Then it can refer to the general section on files for the > basic stuff such as rm. That might be nice > > The man pages for link, symlink, and ln, all sort of gloss > > over the removal aspect. That's putting it mildly :-( > > In short it seems obvious to you and I, but its not > > unreasonable for a new linux user to be confused > > about this point. Thanks. That's what I have been trying to say. Sure, the information is there but the information absorbtion process is greatly slowed, just like putting Windoze on a PC, when one has to chase all over the book and to other sources to get it. > maybe manuals should emphasise the unix idea "everything is a file" more > strongly?! >From other's posts on this topic of links, it seems that it isn't so simple as you say. Trying to pound the idea into a novice only hurts the learning process and he is less likely to understand some of the small details I have just read from this thread. Also, such blanket statements I believe result in people who say things such as "Your regular user needs read and write permissions on sr0 and sg0" without regard to the possibility that the devices might be something else. Posts such as the one from oeren@ykb.com on this list are MUCH more helpful. Though he didn't give the answer, he gave me an idea to try cdparanoia alone. The problem wasn't with cdparanoia but in verbose mode it gave me the information I needed to solve the problem. It seems the device is /dev/sg2, not /dev/sg0. My point is this: making generalizations or expecting the novice reader to fill in info is bad for the learning process. PLEASE try to be more understanding of the novice. This will have at least two benefits for you, the more advanced user. 1. the novice will learn more and learn it more rapidly so that he will then not have to ask so many questions about subjects that you feel you have answered too many times 2. the novice will gain a much better understanding to the point where he can actually contribute to the list and answer for you those questions that you have answered so many times Damon Register
John Andersen wrote:
A link is a file. You use rm to remove a file. The deductive leap isn't that large maybe but I don't think it is unreasonable to want books or FAQs to not leave such gaps
How do I get rid of a member of a partitioned data set on my IBM 370 under MVS?
Get my point? I lost you on that one.
Damon Register
Damon Register wrote:
I am well aware that this list is free and voluntary and that no one is under any obligation to solve my problems so please don't think that
Got it in one. We all try to help but most of us also hold down at least one full-time job.
Another great example is something really simple: symbolic links. I could find information in "Running Linux" (O'Reilly?) on creating a symbolic link but the writer didn't bother to mention how to get rid of a link. This is really stupid. How can a beginner be expected to guess that rm is the way to get rid of a link? [rant off]
This is how it works. You know the answer now, so make it available. I'm not sure who you're complaining about because you're involved too :o) If the FAQ is wrong or incomplete then hammer on Togan's door with the correction/update. We agree to do the same. Damian -- Damian O'Hara using: SuSE Linux 8.0 3:02pm up 17 days, 6:11, 13 users, load average: 0.24, 0.32, 0.28
Damian Ohara wrote:
is under any obligation to solve my problems so please don't think that
Got it in one. We all try to help but most of us also hold down at least one full-time job. That's my problem. I want to learn but I don't have unlimited time
This is how it works. You know the answer now, so make it available. I'm You mean write to Welsh (I think that is the author of "Running Linux")?
If the FAQ is wrong or incomplete then hammer on Togan's door with the correction/update. We agree to do the same. I am planning to do that but before I do, I want to get all the facts straight so I can tell him what I would like to see changed. Isn't that reasonable? I want to get it workinging and learn why. Then I can edit his FAQ from a beginner's viewpoint. I believe that the beginner's viewpoint is needed in many FAQs or instructions. Beginners will have what they need and advanced users can just ignore what they already know.
Damon Register
* Damon Register; <damon.w.register@lmco.com> on 16 Dec, 2002 wrote:
Damian Ohara wrote:
If the FAQ is wrong or incomplete then hammer on Togan's door with the correction/update. We agree to do the same.
You are more then welcomed :-)
I am planning to do that but before I do, I want to get all the facts straight so I can tell him what I would like to see changed. Isn't that reasonable? I want to get it workinging and learn why. Then I can edit his FAQ from a beginner's viewpoint. I believe that the beginner's viewpoint is needed in many FAQs or instructions. Beginners will have what they need and advanced users can just ignore what they already know.
Now to make things clear the document mentioned at http://dinamizm.ath.cx/articles/cdrip.html as it says so is provided by a member of this very list named Keith Winston. He has also provided many other documents. I can not test every document that comes as sometimes the topic is not in my interest area hoewever since I do see lots of questions on the topic I try to evaluate the answers based on my interpretation I include it either as a FAQ entry or as a document. Sometimes the link that the document is refering to is broken the server moved or it does not exits any more name it whatever you want. The only way I can update the Unofficial FAQ is when someone says the XYZ link is broken and here is the new location. Telling the link is broken does not help since I am not going to search where the link is now as per the reason maybe the topic is not in my interest area. That is why I have placed the project on Sourceforge and created trackers for Bugs =========== http://sourceforge.net/tracker/?atid=439827&group_id=42064&func=browse Patches =============== http://sourceforge.net/tracker/?atid=439829&group_id=42064&func=browse When this project started about a year ago there were so many people who offered to help in lots of ways including monitoring specific topics so they would be providing a complete Question and Answer for common topics. Result null, except a very few who helped like Keith. Almost everything is compiled from the mailinglist that means I have to follow the threads trying to figure out is there a solution or not and then get the QA included. Things can go much faster when I have a complete document that all I have to do is format it to Docbook and create the HTML, PDF and the rpms. http://lists.suse.com/archive/suse-linux-e/2001-Nov/2348.html started this project and just follow it and you will see what I mean. Consequently this has become a "one man show", it can only go into the direction that it should go meaning a proper document which has footprints everyone can follow. Yet this the biggest problem of every FAQ unless it is a joint effort. Readers will come to the point that FAQ's should be designed for the beginner and no FAQ exists yet well here is something for you then make it from the eyes of a beginner and either send it to me or place it as a patch/bug whatever at Sourceforge.net. I do not recall I have rejected a document as yet. Hope I have made things clearer now -- Togan Muftuoglu Unofficial SuSE FAQ Maintainer http://dinamizm.ath.cx
Togan Muftuoglu wrote:
You are more then welcomed :-)
Thanks. I will wait until I get enough information so I don't bother you with bits and pieces.
http://dinamizm.ath.cx/articles/cdrip.html as it says so is provided by a member of this very list named Keith Winston. He has also provided I noticed that but I didn't know him.
I can not test every document that comes as sometimes the topic is not I would not expect that and I hope my post didn't seem that way.
broken and here is the new location. Telling the link is broken does not help since I am not going to search where the link is now as per the I printed the FAQ and am marking it as I progress. I would like to submit to you or Keith for approval when I am finished with getting it to work
the threads trying to figure out is there a solution or not and then get the QA included. Things can go much faster when I have a complete document that all I have to do is format it to Docbook and create the Sometimes I feel bad that my novice level keeps me from really contributing to this list as do others like you or Anders Johansson but I think this is an area where I could contribute. When I am able to collect enough information and get this working, I wish to edit the FAQ from a novice viewpoint in order to help others like me.
it from the eyes of a beginner and either send it to me or place it as a patch/bug whatever at Sourceforge.net. I do not recall I have rejected a OK.
Togan, would you be willing to help me with this problem so I can get it working and have enough knowledge to do the FAQ edit? Is anyone else willing to help. I want to do a little detective work to find what are the devices involved and what permissions have to be set. I see that one problem is that everyones system is a little different so it isn't always good to just say something like "set permission on /dev/sg0". I want to be able to say to anyone what steps to take to find what is the case for his/her system and then say how to apply that information. It seems that the SCSI controller permission has to be set but how do I know what is the SCSI device? or in general, what is the device for any kind of controller? What would be the steps I do to find the relationship between pieces of hardware and their place in the /dev tree? I believe this is very important in making the FAQ much more universal. I see that YaST can provide a really nice list of hardware with lots of information about the hardware but as far as I can see it doesn't tell me that my Adaptec AHA2940 SCSI card is /dev/sg0. I really believe that this device and permission issue is common to a lot of problems in posts that I have seen on this list. This is why I want to learn this so that I can include it in an edit of the cd ripping FAQ. Damon Register
* Damon Register; <damon.w.register@lmco.com> on 16 Dec, 2002 wrote:
I can not test every document that comes as sometimes the topic is not I would not expect that and I hope my post didn't seem that way.
broken and here is the new location. Telling the link is broken does not help since I am not going to search where the link is now as per the I printed the FAQ and am marking it as I progress. I would like to submit to you or Keith for approval when I am finished with getting it to work
OK send the final to me or place it as patch to the project at http://sourceforge.net/projects/susefaq
like "set permission on /dev/sg0". I want to be able to say to anyone what steps to take to find what is the case for his/her system and then say how to apply that information. It seems that the SCSI controller permission has to be set but how do I know what is the SCSI device? or in general, what is the device for any kind of controller? What would be the steps I do to find the relationship between pieces of hardware and their place in the /dev tree? I believe this is very important in making the FAQ much more universal. I see that YaST can provide a really nice list of hardware with lots of information about the hardware but as far as I can see it doesn't tell me that my Adaptec AHA2940 SCSI card is /dev/sg0.
Now as far as I know the order is based on which module is loaded first and not only limiting the module but also the hardware addressing. Now with your case AHA2940 is a SCSI card and it can not be /dev/sgX where X is a number. On the otherhand devices you attach to this scsi card will be assigned to respective /dev/sgX based on the above hardware addressing resource usage etc. I know this is not the full answer but should give you a starting point. What I do with scanners and cdwriters is I chown them to root.disk and I add the user in to this group group disk has read wrire permission to the device -- Togan Muftuoglu Unofficial SuSE FAQ Maintainer http://dinamizm.ath.cx
On Mon, 2002-12-16 at 09:40, Damon Register wrote:
I am well aware that this list is free and voluntary and that no one is under any obligation to solve my problems so please don't think that I am unhappy with the people in this list. As I have said in other posts, I would really like to be able to leave the Gates world but so far this has not been possible. Still I am running into a lot of little problems that keep me going to Windows to get certain tasks done because I still can't solve these problems with SuSE.
I think a lot of my problems are permission related but I can't solve them without a little help. With a little detective work I was able to find from fstab and Konqueror file manager all the relationships between CD drives and names. From Konqueror I find that /cdrom is a link to /media/cdrom. fstab shows me that /media/cdrom is a mount point for /dev/cdrom and Konqueror shows me that /dev/cdrom is a link to /dev/sr0. Great, now I have the chain but what do I do with this in order to get grip to work for a normal (not root) user? What permissions must be set? You need to set write permissions for /dev/sg0 to allow write. If you are the only one running the machine, you can do this and see if this helps you out. chmod a+rw /dev/sg0. This should allow anyone to rip CD's from Grip and Konqueror. (I'm sure that I will get slammed on this one) Why does the IDE DVD drive work with no adjustments while the SCSI CD-RW not work for a normal user but does work for root. Is it possibly the SCSI controller that needs permission adjustment? If so, how do I find what is the /dev and what permission must be set? What are you trying to do? If you are trying to burn CD's, then you need to change permissions on the programs.
snipped rant/ I know that the learning curve is very hard to do. I come from a heavy Windows background myself. (Former MCSE). But I have used Linux for a while now and I do agree with some of your points! I have had things along the way that frustrated the living h e double hocky sticks out of me but I still keep on trying (because I'm hardheaded and persistant!). Alot of people feel that one should look at the archives and see if your qusestion was anwsered before. But when you are very frustrated and would like some help, that is the anwser that you get? Hmmmm I would blow my top too! You may write to me off list and I will attempt to help you out in any way that I can. -- Marshall "Nothing is impossible, We just do not have all the anwsers to make the impossible, possible."
Damon Register wrote:
Why does the IDE DVD drive work with no adjustments while the SCSI CD-RW not work for a normal user but does work for root.
Your IDE DVD is a read only device. Almost everything has read permission. Your SCSI CD-RW needs to be able to write, which is a big difference. Only root has almost limitless write permission, so there are few problems with root, except for the fact that that writing power should be reserved for system changes, otherwise the day will come when you WISH you had limited write permission. ;-)
Is it possibly the SCSI controller that needs permission adjustment?
Probably not.
If so, how do I find what is the /dev and what permission must be set?
ls -l /dev/sr0 -- Joe Morris New Tribes Mission Email Address: Joe_Morris@ntm.org Web Address: http://www.mydestiny.net/~joe_morris Registered Linux user 231871 God said, I AM that I AM. I say, by the grace of God, I am what I am.
participants (9)
-
Anders Johansson -
Damian Ohara -
Damon Register -
Dylan -
Joe Morris (NTM) -
John Andersen -
Marshall Heartley -
Ole Kofoed Hansen -
Togan Muftuoglu