Talk to the IBM Linux Hackers

We've all heard plenty about IBM's investment in Linux, but we don't hear much from -- or about -- the actual Linux developers at IBM. This interview is not with one person, but with a number of IBM Linux people spearheaded by Dave Hansen, who volunteered to help us with this interview. Of the group responding to your questions, Dave says, "There are more people, but the majority of the group's skills are represented. No surprise that we'll have our responses reviewed before we send them back to you, but we'll try to expedite that. "A little background: The group's experience is pretty broad. Most members were Sequent employees who worked on Dynix/PTX before IBM acquired Sequent (we are still mostly based in Beaverton, OR). Not everyone was with Sequent; Matt Dobson and Dave Hansen came into the group last summer, right out of college. A few of our Austin colleagues are long time IBM employees who worked on the AIX kernel before moving to Linux. Ask about anything from the rmap VM, to PTX's crashdump facilities, to life in Portland :)

• Martin Bligh - Large IA32 system VM scalability, Specweb, NUMA
• Dave Hansen - Big Kernel Lock, SMP locking, Specweb99
• Matt Dobson - NUMA API/ Documentation
• Rick Lindsley - SMP/NUMA Locking, Performance Tuning
• Patricia Gaughen - Discontiguous Memory for NUMA
• Bill Irwin - VM/rmap hacker
• Hanna Linder - dcache_lock scalability
• Janet Morgan - I/O Scalability
• Ruth Forrester - database/performance/scalability"

As usual, please ask only one question per post. We'll forward 10 of the highest moderated questions to Dave, and run all the answers, verbatim, as soon as we get them back.

Comments

Multi-CPU Scalability

[morbid]

Now that Linux has been ported to run on high-end machines under virtualization, when will we see a kernel tuned for (e.g.) scalability to 64-128 processors natively?

OS Blending

[2names]

Will IBM try to blend aspects of AIX and Linux together, or will the 2 development paths remain discreet?

Re:OS Blending

[2Bits]

As Linux developers inside IBM, do you get to see the AIX source code? If you do, are you allowed to "steal" some ideas from AIX and implement them in Linux? If not, why not, and what's the IBM official line?

Re:OS Blending

[delcielo]

Along the same lines as the parent. Will IBM be porting anything like SMIT to linux? A leaner overall admin utility is desparately needed IMHO.

Features!

[coryboehne]

What *new* feature(s) are you most excited about developing?

from AIX to Linux

[roman_mir]

Care to tell us if there is anything in Linux kernel or other GNU programs that can profit from your previous AIX experience? How big a paradigm shift was it for you to move from AIX to Linux? Were you pleasantly surprised, unpleasantly surprised or not surprised at all with what you saw in Linux kernel? Did you learn anything in Linux that you would like to see implemented in AIX?

The Open Source model

[larry bagina]

IBM will be using linux to help sell their hardware. Other companies have tried this (VA Linux, which owns Slashdot, once had linux hackers on their payroll). Obviously, IBMs hardware is in a different league as an x86 clone, but do you have any thoughts on Open Source business models and their validity? Once the kernel is running smoothly, will you be disposable since the "Open Source community" can continue development for free?

Linux?

[quasi_steller]

Why does IBM feel that Linux is important to IBM, and how important does IBM feel Linux is to the future of computing in general?

Getting your changes accepted?

[korpiq]

Is Linus accepting your changes well? How directly do you submit patches, and what are your experiences on the overall Linux kernel development style?

linux on thinkpads

[Olinator]

IMHO, IBM makes some of the best mobile hardware out there -- one of the professors I support raves about his ThinkPad 600, that went with him into the Israeli desert for several months and is still running strong, no service required -- but the linux support for that hardware has been, um, erratic at best. Yes, we've been occasionally been able to purchase the odd model with linux preinstalled (usually it's *more* expensive than the comparable model with MicroSoft preinstalled, grr) but an awful lot of the hardware (mini-pci modems, &etc) is rather difficult to drive with a penguin behind the wheel. Why does IBM's linux enthusiasm fade so quickly at the small (physical) end of the hardware scale? Is there momentum underway to change this?

Linux On The Desktop

[Iguanaphobic]

Do you see any place for Linux on the desktop? If so, will you be able to fend off the PC hardware group better than the OS/2 group did in the past?

Best way into the Professional Linux world?

[pgpckt]

As many people here, I am a huge Linux fan, but I am so much so that I am trying to figure out how to get into the professional Linux world when I graduate.

I attend Clemson University and am in the Computer Information System (CS + business) program (and doubled in Political Science). My goal is to become a Linux sys admin, or perhaps some other Linux guru type job. The work that IBM is doing with Linux is also very appealing to me.

So, how did you get your job, and what would you recommend as the path to follow for us geeks just getting started in the professional world as to how to get into Linux? How can I become as entrenched with Linux as the professionals at IBM? I have had two internships (not with IBM, nor with Linux, but with other CS stuff), but how can I get an entry-level job in a Linux intensive environment like IBM? How can said job lead me into a career where I can be deeply involved in the Linux world?

distros?

[elykyllek]

I would love to know what distros are popular on your desktops, at work and at home.

Also explaining why you chose that distrobution would be great.

Thanks

Issues with middle management

[Consul]

When you were starting out as a group, did you encounter a lot of friction and resistance from middle and/or upper management about your wanting to work on Open Source projects for IBM? If so, what did you do to overcome the objections and become the team you are now? I think the answer to this would help a lot of other people in other companies get mainstream acceptance of the idea of OSS in corporate environments.

What is Linux Missing?

[dasunt]

What features do you find linux most lacking in?

(If we don't examine our weaknesses, we will be crippled)

When do you estimate Linux can surpass Solaris?

[wytcld]

Solaris 9 is getting great reviews. Between the strengths of the traditional open source community and IBM's resources, do you see a point in the next several years where you expect Linux to surpass Solaris in all of its core strengths? Or does Solaris have some unique values which will allow Sun to continue to position itself to advantage, at least for some applications? Please answer this as a technical rather than marketing question.
___

OS/2 Developers

[reaper20]

I'm one of the few people who really enjoyed the OS/2 desktop and it's features. Have any of the former OS/2 developers been contributing to Linux?

Specifically, the user interface and accessability people - OS/2 was very polished - does IBM see a benefit by offering this expertise to the GNOME/KDE projects?

If so, how does this tie into IBM's vision of Linux of the desktop, if you have one? :)

ViaVoice and Linux -- what's happening?

[xerofud]

I was quite disappointed recently to learn that IBM has discontinued support for the Linux ViaVoice SDK.

What can IBM tell us about the company's future plans for voice recognition under Linux, and in particular, if IBM found supporting the ViaVoice SDK economically unviable, is there any chance that they could open source the code so that volunteers could continue to maintain/develop it?

As evidence of the open source community's interest in the SDK, check out the projects in Sourceforge that rely on it. I just hope that IBM doesn't let the Linux ViaVoice SDK go the way of Blender !!!

IA64

[sabre]

Before IBM downsized the former Sequent hardware division, Sequent was actively involved in IA64 platform design, and continues to be active in many open source IA64 projects...

In general, the Itanium has seen quite poor adoption rates and even Intel/HP admit that their initial public silicon is really only fit for software developers and platform work (due to low performance, and altready established players in the 64-bit field).

Do you think that IPF64 line will see any kind of broad industry adoption? Will it become just like rest of the (non-embedded) processor architectures designed since the x86 -- constantly fighting for 5% of the market? Do you think the AMD Hammer architecture will be a meaningful player in the field?

Since your group is a key player in the Linux on IA64 and GCC for IA64 projects, can you give us any status information about recent developments in the project since the IA-64 Summit?

Thanks,

-Chris

390 code

[buss_error]

What were the major porting problems the 390? Do many people use it? How has management accepted Linux in the 390 world?

IBM Linux?

[sc00p18]

Does IBM have any plans to create its own Linux distribution? Doing so would certainly generate a great deal of publicity for IBM's Linux strategy, as well as serve to make Linux a household name. What are your thoughts on this?

Outstanding Linux Kernel Issues

[worldwideweber]

There are a few debates raging in linux kernel development these days. I was just interested in hearing IBM's take on a few of these subjects:

[1] Rik van Riel VM (RMAP) or Andrea Arcangeli VM?
[2] Is a new kernel build system needed for the linux kernel?
[3] Modules/InitRAMFS or regular ol' monolithic kernel?
[4] Which journaling file system does IBM see becoming the de facto journaling file system for Linux? In other words, what's so cool about JFS :)?

I apologize for sneaking in a few too many questions.

Inter-Company Cooperation

[chill]

From the brief bios, and Sequent pedigree, it looks like there is a lot of focus on high-end features like NUMA, async I/O and the like.

Other commercial organizations, notably SGI, are also putting forth effort in those areas. There is actually quite a bit of overlap.

Since these are "open source" projects, do you collaborate with your traditional "enemies" such as SGI and Sun on Linux? What is your management's attitude towards that type of collaboration? If not, do you "look" at the work the others are doing in comparison to what you are doing?