Editing Phoebe (computer) (section)

==Operating system==
[[File:Acorn Phoebe.jpg|thumb|Phoebe running]]

During the years following the release of the [[RiscPC]], Acorn had discussed using an alternative to [[RISC OS]] as their next operating system, using [[Tao Group (software)|TAOS]]<ref name="acornuser199509_taos">{{ cite news | url=https://archive.org/details/AcornUser159-Sep95/page/n39/mode/2up | title=A thousand and one tools | work=Acorn User | date=September 1995 | access-date=7 November 2021 | last1=Turnbull | first1=Steve | pages=40–42 }}</ref> or writing their own [[microkernel]]-based operating system [[Galileo (operating system)|Galileo]].<ref>{{cite web|url=http://www.iconbar.com/forums/viewthread.php?newsid=1082#cn2|title=The Icon Bar: Clan Newsletters|website=www.iconbar.com}}</ref> However, for the launch of Phoebe 2100 an enhanced version of [[RISC OS]] would be developed, called RISC OS 4 (codenamed 'Ursula'<ref name='ROOL Acorn project codenames'>{{cite web | url = http://www.riscosopen.org/wiki/documentation/pages/Acorn%20Project%20Codenames | title = Acorn Project Codenames | accessdate = 2011-02-03 | quote = Ursula, RISC OS 4.00 (crippled developer release retroversioned as 3.8, see branch Ursula_RiscPC), 1997-8}}</ref>). RISC OS wouldn't support the multiple processor daughter cards that had been included in the Phoebe 2100 hardware specification.<ref name="dev-19971112"/>

RISC OS 4 had to support the new hardware of Phoebe 2100 which wasn't present in Acorn's earlier machines;

* PCI expansion slots<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/PCI.HTM|title=Acorn Computers - Ursula PCI Manager - Functional Specification|publisher=}}</ref>
* Support for multiple serial ports<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/SERIAL.HTM|title=Acorn Computers - Serial Interface Specification|publisher=}}</ref>
* The PC style [[game port]], supporting joystick<ref>[http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERN/RO4/API/JOYSTICK.TXT Acorn Computers - Joystick Module for Ursula]{{dead link|date=March 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> and MIDI<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/MIDIMGR.TXT|title=Acorn Computers - MIDI Manager module 0.00 Functional Specification|publisher=}}</ref>

In addition several new features were to be added to the core of RISC OS;

* A better file system, increasing the number of items in directory from 77 to approx 88,000 and increasing the max length of a filename from 10 characters to 255<ref name="clan-aug-1998"/><ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/FILECORE.HTM|title=Acorn Computers - FileCore - Phase 1 Functional Specification|publisher=}}</ref>
* A plugin based system configuration utility.<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/CONFIGUR.HTM|title=Acorn Computers - Ursula !Configure Changes Functional Specification|publisher=}}</ref>
* A new screensaver API<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/SCREENSA.HTM|title=Acorn Computers - Ursula Screensaver Functional Specification|publisher=}}</ref>
* An enhanced window manager<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/WIMP.HTM|title=Acorn Computers - Ursula Window Manager Changes Functional Specification|publisher=}}</ref>
* An updated interactive help application<ref>{{cite web|url=http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20REFERNC/RO4/API/HTML/HELP.HTM|title=Acorn Computers - Ursula Interactive Help Functional Specification|publisher=}}</ref>
* A redesigned set of icons

To prepare developers for the changes to the OS, Acorn released to its 'Registered Developer' program RISC OS 3.80, designed to load on Acorn's previous generation [[RiscPC]] and [[Acorn A7000|A7000]] computers. This would enable developers to test that their software would be compatible with Phoebe 2100, provided it didn't require any of the new hardware features. RISC OS 3.80 was limited, it only ran on ARM6 and ARM7 RiscPCs and not [[StrongARM]] ([[ARM architecture#Cores|ARMv4]]) based ones.<ref>[http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20Docs/DSNEWS/ART/1998_09.04 Dave Walker - Acorn Developer News 04/09/1998] Softloadable Ursula Image, UrsulaBugs Alias, Updated Tools, etc</ref> Testing of hardware compatibility would have to wait until an initial run of 100 or so pre-production machines was made available to Registered Developers.<ref>[http://www.marutan.net/wikiref/Acorn%20Registered%20Developer%20Docs/DSNEWS/ART/1998_04.17 Dave Walker - Acorn Developer News 17/04/98] Spec Review Aftermath, Developer Conference, UrsMod Tool, Prototype Phoebes, etc</ref>