ALL OUT: Tandy EX PIXMAX + three optional turbo engines, burst / V20 / dirty

Experimental comparison from the owner-verified color-correct PIXMAX default Windows 3.0 image. At DOS (after exiting Windows) run PIXBURST then WIN for two-group unrolling and skip per-group bank wrap when safe; PIXV20 then WIN for NEC V20-only 80186 immediate-count shifts (do not run on stock Intel 8088/8086); PIXDIRTY then WIN to skip matching 16-bit video words after B800h reads. Restore known-good with PIXMAX then WIN, DIBXY then WIN or four-color original with T4CGA then WIN. All original files and the Windows boot logo, mouse, fonts, 16-color panning, three-row groups and old releases are unchanged. Exactly 9 opt-in files added. Compilers, memory limits, bit-order oracle and simulated video-write regression tests pass. Performance or physical graphics correctness of these three experimental drivers is NOT yet confirmed; the dirty comparison could be slower than straight writes. Do not call any new experiment the default until tested on real V20.

Tandy 1000 EX: corrected PIXMAX as default, DIBXY rollback and T4CGA four-color option

This release starts in the owner-tested, COLOR-CORRECTED PIXMAX dual-table 16-color display driver with compact CGA fonts, original 320x200 viewport of 640x256 pannable desktop, BorderWidth=2, original Windows boot logo, unchanged three-row Main/Accessories/Games and serial mouse. Physical Tandy owner measured 18.8-second Calculator startup on PIXMAX RGBFIX and confirmed original colors were restored. From DOS type WIN to launch PIXMAX. To restore DIBXY, exit Windows then type DIBXY and WIN. T4CGA then WIN selects original four-color Tandy display and its wider Program Manager layout. PIXFAST and XRCGA also remain available. This 16 MB image was produced from the checksum-pinned corrected PIXMAX release, changing ONLY WINDOWS/SYSTEM.INI. The original working CF releases, protected gold standard, all games, all fonts, boot logo, mouse drivers, panning and original files are untouched. No claim of further speed gain beyond measured 18.8s Calculator is made.

4K vs 8K RGBI lookup shootout: FAST4K MAX8K BURST4K on owner-tested PIXMAX default

Owner-verified color-correct PIXMAX remains default. Three genuinely larger, independent pixel lookup engines were compiled and installed as optional DOS-selectable Windows 3.0 drivers: FAST4K uses a 4096-byte full-byte four-plane direct lookup; MAX8K uses 8192 bytes of 12-bit three-channel RGB contribution lookup plus 32 bytes for intensity; BURST4K combines the 4096-byte direct lookup with proven two-group burst loop and exact bank-wrap fallback. Exit Windows to DOS, enter FAST4K, MAX8K, or BURST4K, then WIN. Use PIXMAX then WIN to restore normal operation, DIBXY for old 16-color, T4CGA for four-color. Original boot logo, fonts, serial mouse, desktop groups, panning, Windows launcher, and all 426 original files are byte-identical; only nine new optional files added. Passed independent original I-R-G-B palette oracle with exhaustive/random patterns, MASM Windows NE/8086 ISA checks, 192 KiB allocation ceiling and disk SHA256 auditing. These drivers have not yet been tested on physical Tandy; table size can decrease performance.

COLOR FIX: Tandy EX PIXFAST + PIXMAX 16-color speed showdown, original I-R-G-B plane order

CORRECTED November 10 experimental CF image. Supersedes the November 9 PIXFAST/PIXMAX test release which swapped red and blue planes in its lookup converter. Critical fix: exactly match original get_nibble intensity, red, green, blue SHL/RCL bit sequence, verified with an independent one-hot R and B regression plus exhaustive and randomized oracle. The original DIBXY driver and visual appearance are restored, with turbo lookup speed path preserved. Based on the known-good DIBXY 16-color driver (default) and compact CGA fonts. PIXFAST replaces 8 repeated bit-transpose pixels with two word stores using a 512-byte CS lookup table; PIXMAX instead uses two lookup tables (1024 bytes) to remove more shifts. Both preserve original 320x200 viewport, 640x256 logical panning, color mapping, cursor, Windows boot logo, games, protected WIN.BAT, Main/Accessories/Games three-row layout, serial mouse and T4CGA four-color option. Exit Windows to DOS and run PIXFAST then WIN, or PIXMAX then WIN. Run DIBXY then WIN to return to original. Independent baseline assembly I-R-G-B one-hot R/B tests, Python 65536 exhaustive and 250000 randomized RGBI pixel oracle tests, MASM 8086 checks, NE budget and byte-preservation audits all required to pass. This is aggressive experimental conversion, NOT YET qualified on physical Tandy: test correctness before deciding if speed actually improved.

ALL-OUT Tandy EX 16-color PIXFAST and PIXMAX RGBI lookup speed showdown

Separate EXPERIMENTAL CF image, based on the known-good DIBXY 16-color driver (default) and compact CGA fonts. PIXFAST replaces 8 repeated bit-transpose pixels with two word stores using a 512-byte CS lookup table; PIXMAX instead uses two lookup tables (1024 bytes) to remove more shifts. Both preserve original 320x200 viewport, 640x256 logical panning, color mapping, cursor, Windows boot logo, games, protected WIN.BAT, Main/Accessories/Games three-row layout, serial mouse and T4CGA four-color option. Exit Windows to DOS and run PIXFAST then WIN, or PIXMAX then WIN. Run DIBXY then WIN to return to original. Python 65536 exhaustive and 250000 randomized RGBI pixel oracle tests, MASM 8086 checks, NE budget and byte-preservation audits all required to pass. This is aggressive experimental conversion, NOT YET qualified on physical Tandy: test correctness before deciding if speed actually improved.

Verified rebuild Nov 9: Tandy EX DIBXY default + REPIX text repaint, CGA fonts, T4CGA fallback

Verification rebuild on November 9, 2026. This release is required to be file-by-file SHA-256 identical to the November 6 successful release, including the DIBXY default, RPAINT.DRV SHA-256 33e8dfb17b09ad2f0b78199181c51d4aa90ae2e4070696186c7e08fd42463f6d, boot logo, all Windows files, games and layout. Raw CF image SHA-256 may differ because DOS/FAT directory timestamps change on rebuild. Separate EXPERIMENTAL 16 MB CF image. Default boots user-tested DIBXY (XR155+DIB) + compact CGA fonts, 320x200 16 colors, 640x256 panning, three-row Main/Accessories/Games. From DOS after Windows exits run REPIX then WIN to select the new experimental RPAINT.DRV, which conservatively redraws only the columns inside a proven legal Windows text clipping rectangle instead of the entire row; unknown font/clip cases retain the original fallback. Revert via DIBXY then WIN. XRCGA and original Microsoft T4CGA four-color profiles remain available. The beloved Windows boot logo, all games, all original 389+ files, original font and mouse binaries and screen layout are byte-identical to the tested DIBXY base. New driver passes 8086 MASM, NE memory and FAT identity checks, but does NOT have a physical Tandy qualification or proven performance improvement. Never overwrite the gold standard.

Tandy EX Windows 3.0: XR155+CGA default, T4CGA four-color fallback, auto-fit three rows per display

Starts with owner-preferred XRCGA: XR155 16-color 640x256 pannable desktop, 320x200 physical view, compact CGA fonts, BorderWidth=2, unchanged 316px three-row Main / Accessories / Games home screen. From DOS type T4CGA then WIN for original 640x200 four-color Tandy driver with CGA fonts and wider 636px Program Manager with three one-row groups; exit Windows, type XRCGA then WIN to restore byte-identical 320px home layout. All nine existing DOS display/font selectors restore the corresponding Program Manager INI and three PMCC group window rectangles, verified using MS-DOS FC.EXE /B after COPY. Other shortcuts, icon/resource bytes, original Windows splash/boot logo, mouse, font and graphics binaries, protected WIN.BAT, games, panning helper, original backups and gold-standard release preserved unchanged. This is a new build with static verification only; 640-wide window placement awaits physical Tandy test. Requires exiting Windows before changing display/font profile.

EXPERIMENTAL Tandy EX 16-color XR155 fast DIB copy with reversible DIBXY selection

An optional faster bitmap import/export experiment. Original 16-color XRCGA (XR155 + compact CGA fonts) is the initial default and all three adaptive Program Manager rows are unchanged. From DOS type DIBXY then WIN to test XDIB.DRV, a MASM 8086-built XR155 variant with upstream four-byte DIB copy loops unrolled; exit Windows and type XRCGA then WIN to return. T4CGA remains original 4-color Tandy fallback. All original files, logo, fonts, games, saved original layouts, mouse, DOS boot, PAN controls and drivers remain byte-identical; three new files only. Static 8086, NE memory, FAT and contents audits pass, but NO actual speedup or physical Tandy correctness is claimed for this new driver until owner tests.

Preferred Tandy EX Windows 3.0: XR155 16-color panning + clean CGA fonts, T4CGA fallback

Built from the owner-tested corrected DOS switcher CF image. The default after flashing is XRCGA: optimized XR155, 320x200 viewport, 640x256 logical panning, 16 colors, compact CGA fonts, BorderWidth=2 and three stacked Main / Accessories / Games groups. From DOS type WIN. Exit Windows, run T4CGA then WIN to use the original Microsoft 640x200 four-color Tandy driver with CGA fonts (without HPXY panning). To return to the preferred default exit Windows and run XRCGA then WIN. FASTXY selects XR155 with XT fonts, GOLDXY restores original HPXY. Original boot logo and all other programs, games, fonts, display drivers, serial mouse and safeguarded DOS launcher unchanged; the workflow verifies that exactly WINDOWS/SYSTEM.INI and WINDOWS/WIN.INI differ. The old gold-standard release remains untouched. Both XRCGA and T4CGA were user-tested on physical hardware in the prior switching release; this new default-selection disk has passed build validation but is not separately hardware-boot-verified.

EXPERIMENTAL Tandy original 640x200 four-color driver, modern XT/CGA/EGA font switching, XR155 fallback

Experiment on physical Tandy EX. Initially boots the original Microsoft TANDYDSP.DRV 640x200 four-color driver with the updated XTCSYS/XTCFIX/XTCOEM fonts. At DOS, TANDY4/T4XT selects 4-color + XT fonts; T4CGA uses the smaller classic CGA fonts; T4EGA the EGA fonts. XRXT or FASTXY returns 16-color XR155+XT fonts and 640x256 true panning; XRCGA and XREGA pair XR155 with alternate font sets. GOLDXY returns original gold-standard HPXY+XT fonts. Type WIN after each DOS switch; graphics/font selection is not dynamic while Windows runs. PAN is disabled only for four-color (fixed 640x200), automatically restored for XR155/HPXY. Original TANDYDSP.DRV is verified byte-identical to the mouse-tested original Windows image. All EXE/COM/DRV/FON/GRP/logo files, Games, existing three-row Program Manager geometry, COM1 mouse, guarded TGA3+RESERVE+WIN launcher are unchanged. Expected text metrics/compatibility and speed of alternate fonts remain untested on physical hardware. Do not overwrite the gold-standard release.