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Re: Lock-free databases

From: vc <boston103_at_hotmail.com>
Date: 9 Nov 2005 09:46:23 -0800
Message-ID: <1131558383.361855.256810@g43g2000cwa.googlegroups.com>

Joe Seigh wrote:
> vc wrote:
> > Joe Seigh wrote:
> >
> >>vc wrote:
> >>>
> >>>Since they "haven't provided any facts significant to anyone familiar
> >>>with lock-free programming techniques", how can you claim that "
> >>>Lock-free techniques similar to the ones covered by their patents have
> >>>be used in operating system kernels for decades and those operating
> >>>systems weren't going around proclaiming they were lock-free".
> >>>
> >>
> >>Because I used to be a mainframe kernel developer and implemented
> >>some of those lock-free algorithms. In fact I did an RCU implementation
> >>in the mid 80's.
> >
> >
> > 1. How does your being familiar with some lock-free algorithms and
> > having implemented others let you *know* what specific lock-free
> > algorithms ANTs uses (unless you familiar with the patents in question
> > in which case there is a contradiction with your other statement that
> > they "haven't provided any facts significant to anyone familiar with
> > lock-free programming techniques") ?
>
> They haven't quantified the performance contribution of the patents
> and knowing the techniques in question, they'd have to have some
> very specific performance bottlenecks to get a significant benefit.

Could you elaborate a bit on the techniques they used ? Also, where can I find a description of those techniques ?

> >
> > 2. For my own education, while I am aware that IBM/370 had the compare
> > and swap instruction (as well as 'test and set') , what specific
> > lock-free algorithms, other than multiprocessing support, were
> > implemented in the mainframe kernel 20-30 years ago ?
> >
>
> Lock-free LIFO queues and lock-free enqueuing onto FIFO queues.
> Some fast pathed things like WAIT/POST bypass. Examples of those
> were in appendix A for the 370/390/z-Arch Principles of Operation.

OK, I vaguely remember those.

> And an RCU like mechanism in the VM operating system.

Did not know about this one, thought it was a Linux thingie. Thanks.

>Those would be
> the main ones that I can think of offhand.
>
>
> --
> Joe Seigh
>
> When you get lemons, you make lemonade.
> When you get hardware, you make software.
Received on Wed Nov 09 2005 - 11:46:23 CST

Original text of this message

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