ABS Manager - Multiplatform File Manager purely in Python.

ABS Manager is a terminal-only teaching operating system and Windows-backed file manager. It creates normal files and folders in your current directory while simulating OS internals such as block allocation, permissions, process scheduling, deadlock avoidance, journaling, and disk visualization.

No GUI. No web server. No HTTP API. The shell is the product.

Why It Exists

ABS Manager is built for learning by doing. Instead of reading about filesystem trees, block allocation, schedulers, deadlock safety checks, and journals in isolation, you can run commands and watch those systems change in one shell.

It is also practical enough to behave like a tiny file manager: paths such as /docs/a.txt map to real files under the folder where you launched ABS Manager.

Highlights

• Host-backed files: create normal Windows files/folders with ABS shell commands.
• Simulated disk: fixed-size disk.bin, block bitmap, allocation metadata, fsck, and compaction.
• Allocation strategies: contiguous, linked, and indexed allocation per file.
• Filesystem metadata: owner, group, Unix-style modes, timestamps, size, and file ids.
• Scheduling: Round Robin plus priority scheduling with aging.
• Deadlock avoidance: Banker's Algorithm with safe/unsafe request handling.
• Journaling: append-only log, replay, tail, clear, and verification.
• Shell UX: banner, colored agnoster-style prompt, history, completion, pipes, redirects, chaining, scripting.
• Visualizations: blocks, df, tree, fragmap, topb, and full telemetry.

Quickstart

python main.py

Run a one-liner:

python main.py -c "mkdir -p /docs; write /docs/a.txt hello; tree /"

Run the demo:

python main.py demo.mosh

Exit cleanly:

exit

quit, logout, and fmexit work too.

First Commands

mkdir -p /docs
write /docs/a.txt hello
append /docs/a.txt " from ABS Manager"
read /docs/a.txt
realpath /docs/a.txt
tree /
df
blocks
telemetry

Because the filesystem is host-backed, /docs/a.txt becomes:

<launch-directory>\docs\a.txt

Storage Model

ABS Manager operates in the directory where you launch it.

Path	Purpose
Normal files/folders	User-created content from commands such as mkdir, touch, write, cp, and mv
disk.bin	Fixed-size simulated block disk
fs_state.json	Persisted metadata, tree state, bitmap, and allocation records
journal.log	Append-only log of mutating operations
.absmanager_history	Shell command history for the current working directory

rm and rm -r delete real files inside the launch directory. ABS Manager blocks path traversal outside that directory, but destructive commands are still real inside it.

Shell Features

ABS Manager supports common shell workflows:

read /docs/a.txt | grep ABS > /matches.txt
mkdir /tmp && write /tmp/status ok || echo failed
spawn worker 5 3
tick 4 priority
watch ps 1

It also supports:

• Interactive history through readline when available.
• Command, path, PID, and allocation-method completion.
• ;, &&, || command chaining.
• Pipes and output redirection.
• Background jobs with &, jobs, fg, and bg.
• Script files with .mosh.
• POSIX-like exit codes.
• Third-party command execution: any executable on your system PATH (e.g. python, pip, curl, git, node, docker) runs transparently through the same shell, with stdin piping, output redirection, and environment variable support.

Command Reference

Run help, help <cmd>, man <cmd>, or <cmd> --help inside the shell.

Category	Commands
Filesystem	ls, cd, pwd, mkdir, touch, create, write, append, read, cat, cp, mv, rm, stat, find, grep, tree, chmod, chown, du, df, realpath
Disk	blocks, alloc, defrag, fsck, mkfs, mount, umount, topb, fragmap
Processes	spawn, ps, kill, nice, tick, run, pause, top, jobs, fg, bg
Sync / Deadlock	banker, bregister, brequest, brelease, sem, mutex
System	banner, telemetry, log, journal, history, alias, export, env, echo, clear, help, man, version, exit, quit, logout, fmexit, watch
External	Any command on your system PATH — python, pip, curl, git, node, npm, docker, ssh, tar, ...

Architecture

main.py
mini_os/
  core/
    disk.py          # block disk, bitmap, allocation, compaction, fsck
    filesystem.py    # host-backed tree, metadata, permissions, paths
    scheduler.py     # Round Robin and priority aging
    deadlock.py      # Banker's Algorithm
    journal.py       # append-only journal
    kernel.py        # service wiring and persistence
  cli/
    shell.py         # interactive shell and command runner
    parser.py        # pipes, redirects, chaining
    completion.py    # context-aware completion
    render.py        # tables, banner, telemetry, visualizations
    pager.py         # long output paging
tests/
demo.mosh

Preview

export-1779206304014.mp4

Testing

python -m compileall main.py mini_os
python -m pytest

The test suite covers:

• Allocation correctness across all three methods.
• Scheduler fairness and priority aging.
• Banker's Algorithm safe and unsafe requests.
• Permission enforcement.
• Journal replay and persistence.
• Pipe/redirect parsing.
• Completion candidates.
• Host-backed file creation.

Demo Script

demo.mosh exercises the major systems end to end:

python main.py demo.mosh

It creates folders/files, changes allocation methods, renders disk views, spawns processes, ticks the scheduler, uses Banker's Algorithm, checks the journal, and runs fsck.

Safety Notes

• ABS Manager is intentionally scoped to the current launch directory.
• Created files are normal host files.
• rm and rm -r delete real files inside that directory.
• Simulated Unix permissions are separate from Windows ACLs.
• mkfs resets simulated disk state and metadata; it does not intentionally wipe normal host files.