log in | register | forums
Show:
Go:
Forums
Username:

Password:

User accounts
Register new account
Forgot password
Forum stats
List of members
Search the forums

Advanced search
Recent discussions
- Latest hardware upgrade from RISCOSbits (News:)
- Drag'n'Drop 14i1 edition reviewed (News:)
- WROCC November 2024 talk o...ay - Andrew Rawnsley (ROD) (News:2)
- October 2024 News Summary (News:3)
- RISC OS London Show Report 2024 (News:1)
- RISC OS London Show 2024 - pictures (News:2)
- RISC OS London Show 2024 - Notes from the talks (News:)
- RPCEmu 0.9.5 (Gen:2)
- Late breaking news from RISCOSbits (News:)
- ROD updates RISC OS Direct release (News:)
Related articles
- WROCC November 2024 talk on wednesday - Andrew Rawnsley (ROD)
- Rougol October 2024 meeting on monday
- WROCC October 2024 meeting - Andy Marks and RISCOSbits
- WROCC October 2024 talk on wednesday - RISCOSbits
- Rougol September 2024 meeting on monday
- WROCC September 2024 talk on wednesday - Amcog
- Rougol August 2024 meeting on monday
- WROCC August 2024 meeting - Paul Reuvers (XAT)
- Rougol Talk July 2024 - Nathan Atkinson
- WROCC July 2024 meeting - Draw/ROD double bill
Latest postings RSS Feeds
RSS 2.0 | 1.0 | 0.9
Atom 0.3
Misc RDF | CDF
 
View on Mastodon
@www.iconbar.com@rss-parrot.net
Site Search
 
Article archives
The Icon Bar: News and features: Rougol June Talk - RISC OS in those StrongARM days with Mike Stephens
 

Rougol June Talk - RISC OS in those StrongARM days with Mike Stephens

Posted by Mark Stephens on 20:31, 21/6/2021 |
 
This month's online talk was by ex-Acorn and Pace RISC OS programmer Mike Stephens who worked at Acorn from 1994 for about 4 years and 2 years at Pace. He was heavily involved with StrongARM and Phoebe kernel.

Mike started with TI 59 programmable calculator and studied Physics at University. He had a string of home computers including an Acorn Atom, BBC Micro and RISC OS machines. Wrote his own Forth for Acorn Atom.
 
Joined Acorn in July 1994 as a software engineer. Worked on printer drivers and then RISC OS 3.6
 
Really enjoyed the culture at Acorn (and the cake shop round the corner). Concerns at the time over size of market. ARM was the wrong architecture at the time for desktop machines. Thumb instruction set wrong way for Acorn and bloated reference documentation.
 
Worked on verification for the ARM810. Had some powerful features like static branch prediction. Michael wrote a custom kernel. Took some work to get RISC OS running, using a logic analyser to debug issue with double LDM instructions. ARM810 overshadowed by StrongARM.
 
Survived the business reorganisations and change to ART. Desktop business was a cash cow to pay for diversification of Acorn. Only a budget for 2 people on StrongARM upgrade - Pete Fox and Michael. StrongARM was like "the tiger who came to tea".
 
Lots of challenges to make RISC OS run on StrongARM including the new caches. Big headache was altering task swapping for StrongARM. Solved with Application Memory blocks.
 
3.7 booted first time on the hardware but performance not great. Turned out due to not running at full speed (200mhz).
 
His next project was Phoebe's kernel. Also worked on the screen caching, lazy task swapping and speed-ups for Kernel.
 
Continued the RISC OS code improvements at Pace. Moved away from RISC OS after Pace. Back to playing with Forth these days on a Teensy 4.0
 
As always there was time for questions after the talk.
 
Many thanks to Michael for a very nice geeky talk with lots of low level details.
 
Next month will involve some people back in the pub and also online.
 
Rougol website
 
  Rougol June Talk - RISC OS in those StrongARM days with Mike Stephens
  davidb (10:41 22/6/2021)
  markee174 (12:09 22/6/2021)
    davidb (19:47 22/6/2021)
 
David Boddie Message #125143, posted by davidb at 10:41, 22/6/2021
Member
Posts: 147
Were there slides for the presentation? If so, are they available to download from somewhere?
  ^[ Log in to reply ]
 
Mark Stephens Message #125144, posted by markee174 at 12:09, 22/6/2021, in reply to message #125143
Does all the
work around here

Posts: 154
Were there slides for the presentation? If so, are they available to download from somewhere?
Yes. Rougol usually publishes the recording on Youtube.
  ^[ Log in to reply ]
 
David Boddie Message #125145, posted by davidb at 19:47, 22/6/2021, in reply to message #125144
Member
Posts: 147
Excellent!
  ^[ Log in to reply ]
 

The Icon Bar: News and features: Rougol June Talk - RISC OS in those StrongARM days with Mike Stephens