Directory, difference, and buffer editors on CADR and Genera

Entry points and representation

Dired is available as a named Zwei command, as the current-file directory command, and as the Lisp function DIRED, whose standalone top-level editor makes the same mode usable without entering Zmacs first. The implementation selects the special buffer *DIRED*, reads a DIR device stream, and parses each fixed-column row into line properties for first name, version, size, creation date and time, reference date, and status flags. It then marks the interval read-only.

This is a view of one directory at a time. The early code assumes directory output sorted by file name and numeric version so it can compute the highest-version > flag. The mode line carries the device and directory, not a pathname object attached to a unique buffer. That architecture explains why the later System 303 rewrite is more than a command-table expansion.

Complete System 46 local controls

The fixed menu contains increasing and decreasing sorts by reference date, creation date, file name, and size, followed by Automatic and Automatic All. These ten actions, the local table above, and inherited Zwei commands are the complete source-defined System 46 Dired surface at this boundary. Copy, rename, nested subdirectories, load, source comparison, and BDired are not present in this version's local table.

The selected Dired and Standard/standalone tables supply no Abort leaf. An ordinary Abort input is therefore undefined at this evidence boundary, not a hidden “leave without executing” command. The later System 303 and Genera cancellation behavior must not be backported.

Deletion and printing are deferred, but exit is a two-class state machine rather than one transaction. Q first presents and queries Print requests, then Delete requests. Y performs that class sequentially. N returns to Dired. At the Print query, Q or X skips/finishes that class and proceeds to the Delete phase; at the Delete query, Q or X exits without deleting. Per-file string errors are reported and later files continue, so completed prints or deletions survive a later failure or refusal. Automatic deletion retains *FILE-VERSIONS-KEPT* versions (default 2) and treats the configured second names (FN2) MEMO, XGP, @XGP, UNFASL, OUTPUT, and OLREC as its ordinary automatic-cleanup family. It skips rows whose parsed flags contain $. The missing $ command body prevents a source-grounded claim about how that protection flag was toggled.

A pathname-backed, nested view

System 303 creates a unique read-only ZMACS-BUFFER for each Dired invocation, marks its special type :DIRED, and retains a list of exact pathname objects. Each file row stores :PATHNAME and its nesting LEVEL. A Dired buffer can show several directories, expand a subdirectory inside the existing view, and remember which subdirectories were open when the buffer is reverted. Directory operations use the stored translated pathname rather than reconstructing it from display text.

The first column is an operation/state column: D means delete, lowercase d means already deleted, U undelete, P print, F find into the editor, and A apply a function. Exit groups work where file servers support multiple-file operations. Viewing or editing a directory descends into a Dired view rather than treating it as ordinary file text.

Complete System 303 local controls

This is the complete 62-cell local table: 46 direct cells and 16 lowercase aliases. Its named menu commands provide Automatic, Automatic All, and eight increasing or decreasing sort choices over reference date, creation date, file name, and size. A separate file-sensitive mouse menu offers delete, rename, copy, subdirectory, unmark, property change, edit, view, compare, find-on-exit, load, and hardcopy.

S is more capable than its short label suggests. With no numeric argument it inserts or removes the selected subdirectory; an argument can ask for only a wildcard subset. Revert records the open subdirectory pathnames, reconstructs the directory list, and attempts to reopen the same nested views.

Several source-visible failure boundaries are stricter than the manuals imply. Revert deletes the interval before all directory reads and remembered-subdirectory reopens succeed, so an error can leave an empty, partial, or only partly reopened view. Counted D checks :DONT-DELETE only on the starting row, allowing a later protected row in the same traversal to receive a deletion mark. File-property flags mutate the cached row property before the filesystem call, while copy and rename can complete externally before their display rows are fully inserted or refreshed. None of these operations is transactionally rolled back.

The installed > command comes from System 303 patch ZWEI-126-2, not the main Dired body alone. It walks the contiguous same-name/same-type group and stops on the last row before a differing successor, relying on listing order rather than comparing version numbers. Its loop resolves the successor pathname before its intended end test, so a terminal or non-file successor can signal before the explicit end-of- display branch. A compatible strict implementation preserves that evaluation order.

Complete BDired local controls

These are all 21 local cells: 14 direct entries and seven lowercase aliases. Source contains an I/i “Resolve Inconsistency” implementation inside a large COMMENT form, and its table entries are themselves commented. It is unfinished historical code, not an available System 303 command.

The installed BDired Help describes P as a hardcopy operation, but the selected source body prints the transfer-destination object. Copy and Rename also reuse Dired row operations without refreshing :CFILE, so a displayed pathname can retain a stale compiled-file identity. Transfer itself has no overall confirmation: the two compiled-directory graphs enter transfer mode and execute in order, and an error or per-file prompt can leave earlier setup or transfers intact.

Four independent operation columns

System 303 Edit Buffers renders every Zmacs buffer as an ordinary line with four operation columns before its modification marker and name:

Several independent actions can therefore be scheduled on one row. At exit the implementation handles column 1, then printing, selection bookkeeping, and killing. A newly requested kill also requests saving when the buffer needs it and moves the selection mark if necessary.

Rebuild is not initially neutral: it premarks S on buffers that already need saving and . on the most recently used non-editor buffer. Pressing End immediately can therefore save buffers and select another one; it is not necessarily a no-op.

Complete System 303 local controls

These are all 27 local cells: 18 direct entries and nine lowercase aliases.

Runtime observation — System 303-0, session d06-d07-20260718, generation 1, 2026-07-18: the named Edit Buffers command displayed two rows, four action columns, a read-only Edit-Buffers mode line, and visible End/Abort guidance. The 768-by-963 PNG has SHA-256 bfb96fecd7fc0bac92cc795a687eb0b1e938756fab07ccd9a3a28635f4453a0b and normalized-pixel SHA-256 7e7e951204b44fe98b13b8c0d9e0bdc00fcbc25c4476e0ec74bf7650505a1be2. It establishes only this initial visible state, not the later unmark defect or any destructive effect; full portable provenance and publication review are in the CADR screenshot catalog. Published for reviewed fair-use scholarship; MIT, LM-3, and contributors do not endorse this museum.

A source-and-runtime-confirmed unmark bug

The Help text says U cancels every operation on a buffer. The implementation should clear columns 0, 1, and 2, but assigns a space to column 0 three times. In a fresh System 303 run, a row was marked K and P; U removed K while leaving P visible. This is not a hypothetical static-code complaint: source and observed behavior agree, and the installed Help disagrees with both.

The defect is historically instructive because it follows directly from the four-column representation. The later Genera editor uses one action column, so the same class of partial-unmark error cannot occur there.

Two other ordering defects matter to a compatible reconstruction. W retargets the buffer pathname and clears its file identity before output, so a failed write can leave a detached or retargeted buffer. The selected KILL-BUFFER accepts but ignores its no-save parameter, so Edit Buffers can still prompt to save a modified buffer even after N clears the file-I/O column. Earlier per-row and per-column effects survive a later error.

List Buffers is a TV typeout report

Control-X Control-B emits a transient report rather than entering Edit Buffers. Rows follow the current window's buffer history when that option is active, otherwise the global buffer list. A single status glyph is chosen by priority: new file +, otherwise read-only raw 036, otherwise modified *, otherwise blank. Each row is a TV typeout item carrying the buffer object.

Mouse-1-1 selects the buffer. Mouse-3-1 opens the seven-operation row menu in source-registration reverse order: Compile File, Kill, Print, Unmod, Save, Write, Select. These operations take effect independently; the report supplies no modal keyboard table or report-level transaction.

Kill Or Save Buffers is a TV multiple-choice surface

This surface is available as a named/extended command and generic Zmacs menu item; the selected System 303 tables provide no dedicated fixed key. Rows group modified, new, ordinary, and read-only buffers. They offer Save, Kill, UnMod, and a conditional Compile choice for Lisp-syntax file buffers. The chooser owns pointer boxes and bottom-margin Do It and Abort affordances, not an application keyboard comtab.

Default state depends on the exact numeric value: ordinary value 1 selects Save for buffers needing it; Control-U value 4 clears those defaults; Control-U Control-U value 16 selects Kill for every row without clearing preselected Save. Do It moves the current buffer last and performs Save, Compile, UnMod, Kill per row. The same ignored no-save defect means a Kill-only modified buffer can still prompt. Abort or deexposure performs none of the selected actions; an error leaves earlier rows' effects intact.

Complete Genera local controls

The local named command Show File Properties supplements the keys. The fixed menu has 14 items: increasing and decreasing sorts by reference date, creation date, file name, size, and partition; Automatic and Automatic All; Change File Properties; and Describe Attribute List.

An undelete is not represented by a U glyph in this release. U writes a blank; at execution, blank plus the row's independent deleted state means undelete, while blank on an ordinary row means no deferred action. The displayed confirmation choices are Dynamic Windows presentations as well as character choices, so selecting one with the pointer returns the same Yes, conditional Expunge, No, or Abort result. Expunge is offered only when deletion work exists and either the host supports undelete or the mutable always-offer option is true; that option defaults to NIL.

Dired-buffer reuse is identity-sensitive: the requested pathname must be EQ to the stored object, not merely pathname-equal. After confirmed operations, the mutable exit policy retains the Dired buffer by default, may kill it, or may ask; the ask occurs after file effects, so abort there does not roll them back.

Two implementation details extend the manual's task-oriented account. First, before hardcopying, Dired accepts a canonical file type with an installed hardcopy formatter or applies a conservative text heuristic; it rejects known binary or structured types and considers byte size and host machine type. Second, aborting a failed protected buffer rebuild restores only the copied old interval and recorded sort property described above. The configured source default for disposable file types is exactly (:UNBIN :OUTPUT); docstrings that additionally mention Press do not match that default. Because the variable is mutable, its value in the exercised world remains a read-only runtime TODO.

Edit Buffers is a read-only special node with line-property rows

Genera's EDIT-BUFFERS-BUFFER is a read-only special-purpose node whose filter can be absent, one case-insensitive substring, or an OR-list of substrings. A numeric argument to Edit Buffers prompts for one substring; the presentation/internal route can preserve a list. Its heading is a ZMACS-BUFFER-LISTING presentation, so a displayed List Buffers result can be translated directly into an editable list with the same filter. Edit Buffers rows themselves store the actual buffer in the line's :BUFFER property and use an action character at column zero; they are not emitted by the presentation wrapper used for List Buffers report rows.

Unlike System 303, there is one column per row: . marks the current buffer after a rebuild, while D, S, and ~ are deferred actions and blank means no mark. An action overwrites the period. E immediately selects the row's buffer without executing any other marks. Exiting conditionally selects a buffer when point is on a buffer row, then performs saves, not-modified operations, and kills. H automatically marks modified or new file buffers for saving.

Complete Genera Edit Buffers local controls

The source table contains 36 local cells when digit expansion and lowercase aliases are counted. At the surrounding Zmacs level, Control-X Control-Shift-B invokes Edit Buffers in the inspected source; Control-X Control-B is List Buffers. The isolated runtime capture agrees: its Buffers in Zmacs heading, explanatory status-character legend, and unchanged Zmacs (Fundamental) mode line identify the nonmodal List Buffers typeout report. The earlier Edit Buffers classification was a documentation error, not a source/runtime discrepancy.

Source evidence is exact for the selected profile: zwei/zmacs.lisp.~1058~:141 binds C-X C-B to List Buffers and :155 binds C-X C-Shift-B to Edit Buffers; zwei/buffer-editor.lisp.~12~:64-93,155-185 defines the Edit Buffers local table, mode line, and line-property rebuild, while :328-346 defines List Buffers and its presentation-wrapped report rows. The reclassified 1200-by-900 PNG is zmacs-list-buffers.png, SHA-256 970c299ec6f091dd2895022bd24935abb897931110b592e8c3517cde6a936963.

= requires a file buffer with an associated pathname. Its bit-decoded numeric argument uses bit 2 to ignore case and character style and bit 4 to ignore whitespace. This source-visible comparison control is absent from the concise manual description of Edit Buffers.

Runtime observation — Genera 8.5, session d06-edit-buffers-genera-20260719, generation 1, 2026-07-19: explicit modifier events delivered Control-X Control-Shift-B; the mode line identified Zmacs (Edit Buffers) *Edit-Buffers-1* (RO); and lowercase d put D in the single action column. No marked action was executed. The 1200-by-900 PNG has SHA-256 72ab740da8adc1cbe6c1b784ece34679b5b21d12ad01a54a686d53badc1b1de0 and normalized-pixel SHA-256 61469b3f957c209b6860ef00c273393968fc0b735a49466ccce01b992b5ce133. It proves only the recorded entry and visible mark transition; full provenance, shutdown limits, and publication review are in the Genera screenshot catalog. Published for reviewed fair-use scholarship; Symbolics and other rightsholders do not endorse this museum.

List Buffers is a mouse-sensitive report

List Buffers is not merely the non-editable spelling of Edit Buffers. It sorts by recent selection unless *SORT-ZMACS-BUFFER-LIST* is false, shows the buffer name, version or description, and major mode, and emits each row as a presentation. Its status characters distinguish a new or non-file buffer, a modified file, read-only state, and truncation. List Buffers passes no current-period flag, so it neither shows nor explains a current-buffer period; that period belongs to Edit Buffers. A numeric argument filters names by a prompted substring. A concrete live row hit and winning presentation translator remain TODO; the reviewed report screenshot alone does not prove recognition.

Kill Or Save Buffers is a multiple-choice manager

Control-X Control-Meta-B invokes a separate TV:MULTIPLE-CHOOSE interface. It groups modified files, new/non-file buffers, unmodified files, and read-only buffers, then alphabetizes within groups. Without a numeric argument, Save is preselected only where the buffer's :MODIFIED-P :FOR-SAVING result is true: modified existing-file buffers and new/never-read file buffers. An ordinary nonempty non-file buffer can display + yet does not receive the default Save selection. Any numeric argument suppresses default Save, regardless of magnitude.

Each row offers Save, Kill, Unmodify, and Hardcopy. Save or Kill clears Unmodify; Unmodify clears Save but not Kill; Hardcopy is independent. Do It moves the current buffer last and executes the source-defined order Unmodify, Save, Kill, Hardcopy per row. This must not be called a safe order: selecting Kill and Hardcopy attempts the hardcopy operation on the buffer object after removal, and that exact runtime result remains TODO. Abort performs no selected operation; a later error does not roll back earlier rows.

This three-way split is easy to miss in a feature list:

Runtime observation — Genera 8.5, session zmacs-research, generation 1, verified 2026-07-18 and reclassified 2026-07-19: Control-X Control-B displayed the List Buffers typeout report containing *Buffer-2* and *Buffer-1*. Its heading, legend, and unchanged Fundamental mode line rule out the distinct Edit Buffers application. The image remains evidence for the presentation-backed report; its full provenance and publication review are in the Genera screenshot catalog. Published for reviewed fair-use scholarship; Symbolics and other rightsholders do not endorse this museum.

Compare Directories is a Command Processor report, not BDired

No active Genera BDired implementation was found in the selected source corpus. The directory-difference surface is the typed Command Processor command Compare Directories. It accepts two wildcard-version pathnames and an explicitly mentionable Boolean Ignore Versions argument, then obtains both listings and emits up to two separately resortable Dynamic Windows records, one per nonempty difference side. Its six application views are Name, Type, Smallest First, Largest First, Oldest First, and Newest First.

The comparison is metadata identity, not content diffing: name and type are compared with Common Lisp EQUALP, and version is included unless Ignore Versions is true. Device, directory components, and contents are not compared. The command performs no file mutation and owns no raw key, prefix leaf, pointer translator, or menu accelerator; it inherits Command Processor input editing and generic resortable-output behavior. The both-empty, equal-but-not-identical pathname branch and a live six-view report remain explicit runtime TODOs.