Editing Macintosh XL (section)

== Hardware Architecture ==

=== Core Specifications ===
The Macintosh XL retained the Lisa 2/10's hardware unchanged, with MacWorks XL providing the Macintosh compatibility layer:

{| class="wikitable styled-table" style="width:70%; text-align:center;"
|+'''Macintosh XL Technical Specifications'''
|-
! Component !! Specification !! Notes
|-
| CPU || Motorola 68000 @ 5 MHz || 20% slower than Mac's 7.83 MHz
|-
| RAM || 512 KB standard || Expandable to 2 MB (4 MB with mods)
|-
| ROM || Lisa ROM + MacWorks XL || 64K Mac ROM emulated in software
|-
| Display || 720 × 364 pixels || Rectangular pixels (3:4 aspect ratio)
|-
| Display (with Screen Kit) || 608 × 432 pixels || Square pixels like Macintosh
|-
| Storage || 400 KB 3.5″ floppy + 10 MB Widget || Internal hard drive standard
|-
| Expansion || 3 Lisa slots || Not compatible with Mac peripherals
|}

=== Display System ===

==== Rectangular Pixel Issue ====
Unlike all true Macintosh computers, the stock Macintosh XL displayed rectangular pixels with a 3:4 width-to-height ratio. This caused significant distortion when running Macintosh software:<ref>{{cite web |url=https://www.folklore.org/StoryView.py?project=Macintosh&story=Square_Dots.txt |title=Square Dots |author=Andy Hertzfeld |publisher=Folklore.org |access-date=2025-01-25}}</ref>
* Circles appeared as vertical ovals
* Squares looked like tall rectangles
* All graphics appeared stretched vertically

==== Macintosh XL Screen Kit ====
Apple offered the Macintosh XL Screen Kit to address the pixel aspect ratio problem. The kit included:<ref>{{cite web |url=https://lisafaq.sunder.net/single.html |title=The Apple Lisa FAQ |publisher=Lisa FAQ |access-date=2025-01-25}}</ref>
* New 3A boot ROMs
* Modified video state ROM
* Replacement yoke coil for the CRT
* Installation instructions

The Screen Kit changed the display resolution from 720×364 to 608×432 pixels, providing:
* True square pixels matching the Macintosh
* 50% more screen area than the Mac's 512×342 display
* WYSIWYG compatibility with Macintosh software
* Professional appearance for graphics applications

=== Memory Architecture ===
The Macintosh XL's memory configuration provided significant advantages over contemporary Macintoshes:<ref>{{cite web |url=https://retrocomputing.stackexchange.com/questions/5337/was-the-mac-xl-hardware-different-from-the-last-versions-of-the-lisa |title=Was the Mac XL hardware different from the last versions of the Lisa? |publisher=Retrocomputing Stack Exchange |access-date=2025-01-25}}</ref>
* '''Base configuration:''' 512 KB using 256K×1 DRAM chips
* '''Expansion options:'''
''' 512 KB card (1 MB total)
''' 1.5 MB card (2 MB total)
''' Third-party modifications up to 4 MB
''' XLerator board up to 8 MB

=== Storage Subsystem ===

==== Widget Hard Drive ====
The 10 MB Widget drive was standard equipment, providing:
* 65 ms average seek time
* Built-in controller with diagnostic ROM
* Direct parallel port connection
* Significantly faster than external ProFile drives

==== Floppy Drive ====
Single Sony 400 KB 3.5″ drive (MP-F51W):
* Variable speed rotation (394-590 RPM)
* Single-sided operation
* Compatible with Macintosh disks under MacWorks
* Upgradeable to 800 KB with Sun Remarketing kit