Ask Moshe Bar about [your choice here]

Moshe Bar is (pick one) 1. A Linux kernel developer; 2. A motorcycle enthusiast; 3. The primary openMosix maintainer; 4. A respected Linux device driver writer; 5. Author of several books and many articles about Linux; 6. Newly married. 7. A Talmudic scholar; 8. All of the above. The correct answer is 8, and since in addition to (or perhaps because of) all this Moshe is a popular guy, this interview is here by reader request. (Yes, we take interview requests; send them to [e-mail].) Ask Moshe whatever you wish, one question per post. We'll send him 10 of the highest moderated questions and post his answers as soon as he gets them back to us.

Bikes

Why did you choose a Harley Davidson? Just curious.

Most important question.

Where do you find the time for everything?

Re:Most important question.

To make a more specific version of the parent question:

You do all that and have a wife? How can you possibly find time for her? Does she want more time? Does she kernel hack with you?

Sidenote: Before people bitch about the 'one question rule', all of it could be slurped up into one question, I just broke it down so that its more readable :-P

As a device-driver writer...

It seems like such a chore to write drivers that work on all distros since they all use different kernels. It seems to me that businesses only develop for windows because they are guaranteed that their drivers will work on all windows machines for X (4,5,6) years without any mroe work. Having experience writing Linux device drivers, do you think that a cross-distribution effort to standardize on kernel versions and guarantee major hardware manufacturers this compatibility would promote driver development in Linux?

Open Source

What is your opinion of the current state of the open-source community at this time, and do you think open source beer has a future?

Also, Do yout think that Germany's swich to open source will have a signifigant impact on the open source community and/or IT in general?

I have only one question:

Does Moshe have a son/daughter named "foo"?

openMosix

What is the major difference between openMosix and Mosix, and what do you think openMosix needs to improve on the most?

Getting started as a kernel developer...

As an avid Linux user, and programmer, I've always been interested in developing the kernel. However, the sheer size of the kernel has been rather intimidating, and kept me away from it. I've also found myself to be better at programming "utilities" rather than "end-user" types of programs. Is there any section of the kernel that would be "the best place to start"?

With that in mind, are there any suggestions you could make to those of us interested in kernel development, on how to get started?

Thanks up front.

Talmud and Technology

We have already seen the Islamic religious authorities having to deal with the question of whether divorce via e-mail is binding. What do you see as the biggest and/or most interesting questions regarding Talmudic teaching as they apply to current/near-future technology?

Different social groups

As someone involved in many different activities, do you have cohesive social groups? That is, do the people from, say, your motorcycle-riding friends develop/use linux as well? (Or does your wife know about your dirty little secret? [kernel.org] :P) I'm interested in knowing what your social ties are, being as it seems you are a fairly active individual.

BitKeeper

Despite staunch opposition [iu.edu] from certain developers, Linus has recently started [google.com] to maintain the kernel [bkbits.net] using the non-free BitKeeper [bitkeeper.com] SCM product, which is not only proprietary but also uses undocumented file formats, making interoperability difficult or impossible. Do you think it's fair to encourage developers who would otherwise keep to Free Software to turn to a proprietary solution and what is in effect, shareware?

Linux and Jewish Law

I understand that a lot of Jewish religous law about technology is based around the 'started fire' idea. Forgive me for not knowing more about it as I'm not Jewish, but the way I understand it, a fire cannot be started on the sabbath, but a fire can be maintained during the sabbath.

By the same doctrine, computerized systems can be booted on the day before the sabbath and then put on an autmatic mode during the sabbath. During that time, a sysadmin can address important issues as they creep up, just like he would add a log to the fire he started before the sabbath.

Right? Please correct me if I'm not.

Okay, this said, is Linux kosher for the sabbath? Is it permissable to say, perform a checkfs during the holy day? What tasks can you perform and what tasks can't you?

Re:Linux and Jewish Law

However, there are numerous situations where making fire can be considered play.

Not by orthodox jews. "Work" is probably a poor translation into English of what is forbidden on the Sabbath. For example, a Rabbi and his staff are permitted to do their jobs on the Sabbath (it is their job). Likewise, there are several leisure activities which are forbidden. So the distinction isn't "fun vs. not fun" or "making money vs. not making money". Even if you like playiung video games or want to watch the hockey game, you can't.

"Doing Work" really means "using technology" or "doing creative things" or "transporting large objects outdoors", etc.

Note that I'm not Jewish either, but for 2 1/2 years I rented a basement apartment from an Orthodox Jewish family and learned a lot about the religion at that time.

An excellent read is Judaism 101 [jewfaq.org]

.

As a device driver writer...

do you think that the Linux kernel should follow the same route as the Mozilla project. That being that when Mozilla reaches 1.0 the API will freeze and any plugins, applications that use gecko, etc. will be compatible until version 1.2 is out. Should the Linux kernel make some sort of standardized API for drivers so a driver that works with 2.4.0 will work for 2.4.20?

Is this a reasonable request? (doable?)

why/why not?

What was their expression???

After reading this cheerful little event [moshebar.com] I decided to ask you: what was the expression on the faces of these Microsoft executives, when you delivered your speech about Linux?

Talk about priceless :o)

Database Clusters

As a cluster guru, I am curious about your take on database server clustering in both the commercial and the open-source space.

First, it appears that IBM DB2 has been wiping the floor with Oracle on the TPC benchmarks lately, and Oracle "RAC" has been a flop. However, IBM is not using any hardware from its proprietary server lines, but instead relies on clusters of "federated" databases running on 32 standard PCs running either Linux or Windows. It does appear that Oracle still generally beats IBM in raw performance on a single system (as IBM refuses to post any non-clustered benchmarks AFAIK).

Do you think that any of the hype over either of these vendors cluster packages is worth attention? Do you agree with Sun's claim that TPC(-C) no longer has any practical relevance? It all seems to be getting rather silly.

Second, is there any push to make any of the ACID-leaning open databases (Postgres, SAP-DB, etc.) fault-tolerant, perhaps using Mosix? I assume this would require modifications to Postgres enabling it to access raw partitions. Have you had any talks with the Red Hat Database people about cluster modifications to Postgres, just out of curiousity?

Motorcycle Question

What do you think of the return of the Indian [indianmotorcycle.com] brand?

As for me, I think someone is cashing in on a classic. Tis a shame.

Not about Linux at all...

...but the article said pick anything. Since there are quite a few philosophers on Slashdot (and since I'm Jewish and this question gets a lot of thought from me, and when will I ever be able to ask again?) here's my question:

Do you see any reconciliation between science and the G-d of the Torah? What about between Science and any sort of Creationism at all? Do you see the possibility that science, as it approaches the moment of Creation itself, becomes more in tune with religion? I guess a big part of what I'm asking - do you see a place for (or proof of) G-d in science?

Thanks...sorry this isn't the usual Slashdot fare, but I can't help but ask.

ok, so I admit it...

I have no Idea who you are.

however, it says here you develop drivers.
how does one get into that sort of thing starting out? obviously you've been doing it for a while. how would someone who has a base understanding of assembly and C get into this? it's a big field, and I wouldn't know where to start, but I would like to help some day.

What area of law are you studying?

According to the FAQ [moshebar.com] on your website, you are currently studying for your first law degree. With such a heavy technical background, especially in CS, I am curious as to what area of the law you are planning on going into. Is it a technology-related area? It would be nice to have some more technically-capable people in the law profession, especially those who are Linux friendly. Or is going into law just your way of making money for that early retirement?

UnitedLinux

What are your feelings toward UnitedLinux? Do you feel that it is a blatant misuse of other people's hard work, or is it merely a misunderstood attempt to standardize the vast differences between various Linux distributions? Lastly, do you feel that Linux needs this sort of standardization in order to succeed in the business world (both server and desktop markets)?

Which one?

1. Emacs
2. VI
   

Single Memory Space for openMosix

Right now, as you've mentioned in the documentation, programs that access databases or shared memory do not derive any particular benefit from using openMosix.

Is there any work planned to enhance openMosix to support a single memory space among all nodes or to otherwise allow implicit sharing of memory? Is this what the "network RAM" research is attempting?

Implementing something along these lines in an efficient manner would hugely expand the range of problems that openMosix could be used to tackle.

Imagine being able to split a database transaction into hundreds of parts and run it in parallel on hundreds of openMosix nodes with a terabyte or more of combined RAM. The processes that share data would automatically migrate to the same node. Mmmmm good!

Congratulations...

... on your recent wedding.

Introducing a Ms. usually complicates the hacker lifestyle. Despite good intentions on both sides, scheduling conflicts erupt and something has to give.

How well does Ms. Bar understand your {"fascination", "interest", "obsession", "devotion"} to computing? How about your other hobbies and interests?

IBM and Hercules?

(I'm the maintainer of Hercules [conmicro.cx], an open source emulator for IBM mainframes that runs on Linux and Windows.)

You've mentioned Hercules in your column a couple of times, both quite favorably. Thanks!

One industry analyst from Germany has claimed repeatedly that IBM is getting ready to slap down Hercules with its lawyers, on the basis of some unspecified violations of their intellectual property rights. He's said that it's not just patent infringement, but refuses to go into exactly what else.

What effect would you think that taking such an action would have on IBM once the open source community finds out?

Thread migration

One of the advantages of OpenMosix is that programs do not need recompilation or any special design techniques to take advantage of clustering.

This design goal isn't always realized though, because OpenMosix works with processes as the atomic work-distribution unit, and not treads. ie. OpenMosix can't migrate multithreaded apps.

Is thread support planned for *any* future version of OpenMosix?

a mature kernel?

Great software projects may (should?) eventually mature to the point where they don't need to change anymore. A classic example is TeX, whose version number is converging to pi. Is there a point at which the Linux kernel will become a mature project, and most of you smart kernel hackers can turn your talents to other open-source work? As a desktop user, it seems to me that the kernel has already reached that point; the only time I ever run into low-level system bugs, it's always X bugs, not kernel bugs. Is it getting to the point (e.g., with virtual memory stuff) where any change you can make will cause the kernel to perform just a little worse for some people, and just a little better for others?

I can't help thinking that the Linux kernel may be a little like string theory in physics. String theory tends to attract young people who are the most talented of all, and you have to wonder whether their talents are being wasted, since string theory might not even reflect reality.

Practical OpenMosix

What are some of the most interesting computing projects you've heard about using MOSIX that could pretty much only happen using MOSIX (as opposed to "plain old" PVM/MPI/etc)?