Sirius DOS

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Sirius DOS
Created by				Alexander Nicholi
Written in				C, C*, x86 assembly
ISAs				i286, i486, and more
Licence				ASL 1.1

Sirius DOS is a research software platform devised by American computer scientist Alexander Nicholi based on MS-DOS 6.22 and running on IBM-PC compatibles.

Purpose

The 16-colour, 32×32 pixel icon for Sirius DOS.

TBW

Hardware

There are several categories of hardware that are considered for a support spread: CPUs, video cards, monitor resolutions, multimedia drives, and network stacks.

CPUs

Genuine Intel i286 @ 12MHz (GRiDCASE)

Genuine Intel i486 @ 75MHz (Compaq LTE Elite)

Cyrix 5x86 @ 100MHz

AMD i486-compatible chip (?)

Genuine Intel i686 (?)

Video cards

IBM CGA mode 3 (80×25 text w/ colour)

S3 ViRGE VX with at least 4MiB VRAM

Cirrus Alpine CL-GD5480 with 4MiB SGRAM

Displays

CGA monitor (?)

19" Sony Trinitron running at 1280×1024 @ 60Hz

18" Compaq 151FS running at 640×480 @ 75Hz

Multimedia

NEC FD1231H 3½" floppy drive (A:)

NEC FD1157C 5¼" floppy drive (B:)

64 MiB industrial CF card with IDE adapter (C:)

Creative Labs CD5233E CD-ROM drive (D:)

Creative Labs CT1870 CD-ROM ISA controller card

Greystone dual-slot PCMCIA reader with ISA controller card

Osprey Video 22-02028-03 PCI VGA + ⅛" audio capture card

Network stacks

RS-232 Serial based protocol (TCP?)

3Com EtherLink III 3C509B-TP 100 Mbps Ethernet ISA controller card

ABIs

Sirius DOS has two ABIs that it strives to target: the Optic ABI, serviced by Sirius A and B, and the Prime ABI, serviced by Sirius A′ and B′. Sirius V also adaptively services both ABIs (V being Optic and V′ being Prime).

Optic ABI

The Optic ABI is the more fully-featured ABI which provides unencumbered pel-exact video access in 15-bit RGB555 colour, specifically at two resolutions: 640×480 and 1280×1024. The Optic ABI is key for Quindle, which leverages it to provide a great editor experience. Other products that service the end user may also come to depend on this ABI.

Despite running only on i486s in hardware, the Optic ABI is tied to the i286 for its machine code compatibility, just like the Prime ABI.

Prime ABI

The Prime ABI only supports text mode interfacing, albeit at arbitrary vertical resolutions (80 characters is always assumed). It is provided for the sake of many utility programs that are designed to be highly automation-friendly or UNIX-principled, especially on older versions of DOS and on older machines, even back into the mid-1980s.

Virtual Prime

The Prime ABI is also available to be run in the Optic ABI using a "virtual console" type approach, where it may be possible to leverage other fonts and sizes.

Hybridism

Hybrid programs are a central feature of Sirius DOS where programs can have graphical output and text console I/O together with a unified interface. In its most basic form, the kernel monopolises a special key (or keys) for use in toggling the view of the output between the graphics and the console, so no matter what the program, the same method can be used by the user to switch.

Quindle also provides a more flexible built-in system of running hybrid programs.

ISA levels

There are several feature levels that Sirius DOS and other platforms such as A* and MILOTIX provide for targeting by application code on the x86:

• Level 1
  • i286 and earlier instructions
  • no x87 floating point
  • real mode
• Level 2
  • i486 and earlier instructions
  • x87 floating point
  • real mode
• Level 3
  • i686 and earlier instructions
  • x87 floating point
  • MMX SIMD instructions
  • real mode
• Level 4
  • earliest 64-bit support
  • SSE3 and earlier
  • pegged to Nocona and Silverthorne µarches
    • more precisely, the exact feature set is the intersection of Nocona and Silverthorne feature sets
  • long mode
• Level 5
  • more recent 64-bit ISA
  • SSE4.2 and earlier
  • pegged to the Silvermont and Nehalem µarches
    • more precisely, the exact feature set is the intersection of Silvermont and Nehalem feature sets
    • unfortunately this means no RDRAND, CLMUL, POPCNT or AES-NI
  • long mode
• Level 6
  • more recent 64-bit ISA
  • SSE4.2 and earlier
  • AVX and AVX2
  • pegged to the Knights Corner and Haswell µarches
    • more precisely, the exact feature set is the intersection of Haswell and Knights Corner feature sets
  • long mode
• Level 6a
  • Variant of level 6 that permits Knights Corner's Intel Many Core Instructions, the ancestor of modern AVX-512 SIMD extensions
  • long mode
  • It is otherwise limited entirely the same as level 6 is
• Level 7
  • (currently as of this writing) most recent 64-bit ISA
  • SSE4.2 and earlier
  • AVX and AVX2
  • AVX-512, specifically:
    • AVX-512F
    • AVX-512CD
    • AVX-512DQ
    • AVX-512IFMA
    • AVX-512BW
    • AVX-512VL
    • AVX-512BF16
    • AVX-512VBMI and AVX-512VBMI2
    • AVX-512VNNI
    • AVX-512BITALG
    • AVX-512VPOPCNTDQ
  • pegged to the Zen 4 and Sapphire Rapids µarches
    • more precisely, the exact feature set is the intersection of Zen 4 and Sapphire Rapids feature sets
  • long mode
• Level 7a
  • Variant of level 7 that is devolved to better support Knights Landing µarch
  • The exact feature set is that of level 6, plus AVX-512F and AVX-512CD
  • long mode