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 robin@roblimo.com.) 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.

Comments

Bikes

[crumbz]

Why did you choose a Harley Davidson? Just curious.

Re:Bikes

[Altus]

Why anyone would ride a bike with a V-6 cramed in to a tiny little space I will never know.

I have never liked the Valkarie. In addition I realy dont like the styling on any of the newer honda cruisers. for styling reasons alone, I would buy a V-star or Road-star before a recent model honda. Its just my opinion of course, other people might love them, but they just dont do it for me.

I used to like the Kawasakis but for reasons unknown the look of the 1500 cruiser do much for me anymore, and I think the roadstar is a better deal.

The reason I dont buy an old bike is that I dont have the time or skill to do a full rebuild on a bike... The new 88 ci engine from harley is a beautiful piece of work, and it will provide me with all the hours of riding that I desire this summer, and this winter I can tear it down and get my hands dirty.

thats what I am looking for in a bike, and the harley delivered it nicely. It also helps that I got a good deal on a bareley broken in 2000 FXDL (under 5k miles) with plenty of extras on it, most of which were things I would have spent money on anyway.

Dont get me wrong. I hold no ill will to japaneese bikes (even sport bikes, I kind of like them actualy) and you definitely pay a premium for the harley davidson, but for me, it was worth the money to get the exact bike I wanted. hopefully, with proper maintinence I will be riding it for years to come.

What's your primary browser?

[Anonymous Coward]

Mozilla, Opera, Netscape, Galeon, IE, lynx? Which is it?!

Time

[rnb]

How do you find time to follow all of your interests?

Open Source

[TweeKinDaBahx]

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?

openMosix

[MBCook]

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...

[PM4RK5]

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

[valdis]

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

[CAIMLAS]

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? :P) I'm interested in knowing what your social ties are, being as it seems you are a fairly active individual.

Favorite historical figure..

[mrgrey]

He also has a long-standing love-affair with Israeli history.

What is your favorite Isreali historical figure?

Linux and Jewish Law

[Bonker]

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

[Otter]

I understand that a lot of Jewish religous law about technology is based around the 'started fire' idea.

It's more that electricity is classified as 'fire' and electrical devices are subject to the laws governing fire. That is the case when the electricity has the potential to create a fire, because it creates heat or sparks. Solid-state electronics and LEDs are a different matter, but that's getting into some obscure rulings and in practice almost all electrical devices are treated as fire.

but the way I understand it, a fire cannot be started on the sabbath, but a fire can be maintained during the sabbath...just like he would add a log to the fire he started before the sabbath.

No, the fire can't be touched at all, except for reasons of safety. On holidays, which have a weaker set of restrictions, the fire can be tended.

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.

That's a different issue -- if a cron job or something similar is configured before the Sabbath starts, there's no problem with its running itself. Most religious Jewish homes have lights connected to timers for precisely that sort of thing.

Re:Linux and Jewish Law

[The Wing Lover]

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

.

As a device driver writer...

[dalutong]

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???

[haggar]

After reading this cheerful little event 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

[emil]

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?

the future of linux

[larry bagina]

Linux (as is a lot of open source software) is mostly just a reimplementation. Although there are some novel ideas, unix, clustering, etc, were done by others years ago.

Do you think the linux kernel, openMosix, and Open Source in general can break out of that stereotype?

Motorcycle Question

[w.p.richardson]

What do you think of the return of the Indian brand?

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

Re:Most important question.

[FortKnox]

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

linux filesystems

[Anonymous Coward]

since as is the linux filesystems book is horrible
(most structural basics and concepts are not explained but
just used, maybe a third of the book are sourcecode
dumps and partly very outdated howtos) will you finish it
and bring it into a form that makes it worth buying?

Tomas Pospisek

ok, so I admit it...

[morgajel]

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.

status of migrating sockets development

[Kz]

For me, that's the main thing that i fear of "fork and forget", a non-migrating socket would easily double the network traffic on a cluster... but i've never been able to found any word of progress on this area.

And what about other forms of IPC communication? is there a (performance) contrainidication on their use on mosix clusters?

What area of law are you studying?

[gosand]

According to the FAQ 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?

IBM and Hercules?

[Jay Maynard]

(I'm the maintainer of Hercules, 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

[Bobo_the_Chimp]

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?

[bcrowell]

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.

People of faith in Free Software

[sombragris]

I understand that you're a Talmudic scholar. This is interesting in itself since most of the highest profile members of the Free Software community usually express anti-religious ideas or are from religious traditions drastically at variance with the Judeo-Christian traditions (ie, neo-paganism and oriental misticysm).

How is that you relate your Jewish faith with the work as a Free Software developer, and the central tenets of the Free Software movement?

Honesty

[Anonymous Coward]

Hi Moshe,

Remember me, Mark?

I have a question for you.

When you hire someone from abroad to do something for you, and you make an agreement in advance about what he gets for it.
What do you do? Do you keep your word or are you just a lying basterd?

Thanks for your time.

Mark Santcroos

ps. I hate begging for money, but I couldn't let this opporturnity go by.

Practical OpenMosix

[bozoman42]

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)?

a liittle clarity on the Jewish p.o.v.

[space oddity]

I have not ever been tempted to post on /. but there is always a first time.

There have been a lot of posts about conflicts or lackof with Halachik (orthodox) Judaism and tech. I'm sure Moshe knows his stuff and I'm also sure that he would be embarassed to be called a Talmud scholar. However, could he/you perhaps spend some time dispelling myths and explaining facts about some of the issues. I don't think a discussion on using email as a shaliach (third party) for divorce papers is necessary or the difference between "G-D" on paper and "God" on a computer screen (which is a comlex issue. But ideas about how the sabbath fits in with practical life and place of God in his personal life would be illuminating.

Useless use of linux

[the_real_tigga]

What is the most useless / weirdest / hackish / funny "feature" that you ever saw on a linux machine or in a proposed kernel patch?

What would you like to see on linux that would fit that category?

Fast compile server

[Snake]

Like every decently equipped developer, you have a compile server. However, you recently (2 months ago, IIRC) said that you wanted to accelerate the speed of compilation.

What solution have you used?

Did you look at using ram disks?