[parisc-linux] HP open sourcing the SOM linker

[parisc-linux] HP open sourcing the SOM linker

[Alex deVries]

Hewlett-Packard, in co-operation with the Puffin Group, is open sourcing
their SOM linker product.  This release is an important step in the
project to port Linux to the PA-RISC architecture, as it will eventually
allow developers to more easily test their work.

32-bit versions of the HP/UX operating system use a proprietary SOM
(Spectrum Object Model) binary format to load executables, making it a
natural choice as an object format for early PA-RISC/Linux.  Until
now, there was no way to generate a SOM binary except by using HP/UX
tools, which prevented developers from building on any other platform.
Once the port of the linker is complete, developers will be able to
build from a variety of platforms, taking advantage of more computing
power, and reducing the amount of time that it takes to test new code.

Hewlett-Packard, adding to their extensive list of Linux-related
projects, has made the linker available under the GNU General Public
License, making it freely modifiable and redistributable.  However,
though Hewlett-Packard encourages developers to extend and port their
linker, they do not guarantee that community modifications will be
re-integrated into their official product.

Although the linker does not yet produce functional binaries,
developers and curious hackers are invited to browse the source and
commit patches.  HP's official release, as well as future snapshots,
can be obtained via FTP from
ftp://puffin.external.hp.com/pub/parisc/linker, or from the Puffin
Group's CVS server.  More information regarding CVS can be found at
http://www.thepuffingroup.com/parisc/cvs.html.  Questions about the
SOM linker can be directed to linker-info@thepuffingroup.com.

- Alex

-- 
Alex deVries
Vice President of Engineering
The Puffin Group

[parisc-linux] Parallel port hardware

[Sandy Harris]

Can anyone point me to info on the electrical properties of the parallel ports
on 712 or 715 machines?

The Papers project (Purdue Adapter for Parallel Execution and Rapid Synchronisation)

http://garage.ecn.purdue.edu/~papers/Index.html

have an interesting approach to building parallel machines.

Oversimplifying their fairly complex analysis (see page above for details), they argue
that the hard issue is latency for synchronisation, not bandwidth, so you can do a lot
of fairly interesting things with very simple synchronisation logic attached to a
parallel port and software that exploits it from user space, without the overhead of
kernel calls, packetisation, device drivers, .... 

Their most complex device has a few dozen TTL logic chips. Their simplest one handles
up to about 8 machines using just a cable and their software on Linux PCs:

http://garage.ecn.purdue.edu/~papers/WAPERS/

I'm thinking that 8 715s might make an interesting parallel engine, but the cable device
only works if the parallel port's control lines are implemented as open collector TTL.
Where can I discover whether they are?

Re: [parisc-linux] Parallel port hardware

[Alex deVries]

Sandy Harris wrote:
> 
> Can anyone point me to info on the electrical properties of the parallel ports
> on 712 or 715 machines?
> 

The electrical properties of the parallel port are likely identical to
that of the rest of the parallel ports in the world.  The only document
I've ever seen on the parallel ports of the 712 are in the Lasi
documentation.

- Alex

-- 
Alex deVries
Vice President of Engineering
The Puffin Group