Shows memory as pictures. Width W is in pixels and is rounded to whole bytes: 8 pixels (ZX, VGA) or 2 pixels (EGA). Height follows window.
Live view: memory is redrawn 25 times a second while emulator runs; in debugger stopped state is shown.

Modes

ZX

1 bit per pixel, square pixels

VGA

1 bit per pixel, narrow (640×200)

EGA

ATM 320×200, 16 colors, 2 pixels per byte

Memory

CPU 64K

as paged in now

RAM

all pages in row, address page:offset

ROM

all ROM pages in row, page:offset

A: … D:

floppy image in drive (TRD order; iS-DOS as ISD), offset in image; read when chosen (Live view: every second, off for disk by default)

Keys

↑↓ / ←→

line / byte

PgUp PgDn

page

Home End

start / end

Ctrl+←→

width

M

mode ZX / EGA / VGA

Z

zoom 1x / 2x / 4x

I

inverse

G

enter address

F1

this help

Esc

close

Mouse

wheel

8 lines

Shift+wheel

1 byte

Ctrl+wheel

page

drag

scroll lines and bytes

orange line

drag to change width

window edges

drag to resize window

scrollbar

jump anywhere

hover

byte address in status line

Keys work while window has focus. − / + buttons repeat when held.

Emulator keys

REST API

Start a machine, disks and programs from a link: Tools / REST API link (? there lists every parameter).

PC keyboard → ZX

ATM mode (XT keyboard) → ZX

Turbo 2+, xBIOS, ZX-Evolution with ATM mode on (XT icon, bottom left): keys go to ATM keyboard controller. CP/M and other ATM programs get PC keys; ZX programs get ZX keys from controller's own table. On-screen XT panel sends same keys as real keyboard.

Mouse

Screen corners

Files

Two panels, each on drive: A: / B: (TR-DOS, ATM CP/M, Profi CP/M .PRO, iS-DOS floppies), HDD 0 / 1 (ATM CP/M, iS-DOS or FAT drives), SD card (FAT), RAM (scratch disk for this session). Active panel has orange frame; changes go to image right away (drive gets * mark: save it with Save).

Keys

Tab

other panel

↑ ↓ Home End PgUp PgDn

move

Space / Ins

select; + all, − none

Enter, double click

open folder; run file (TR-DOS on A:, CP/M .COM): machine is reset; disk image (TRD, SCL, FDI, UDI, TD0, ISD, PRO, DSK, IPF) on HDD / SD card / RAM: mount into drive A: or B:

Backspace

folder up

F2

re-read both panels

F3

view (text / hex / Z80 code)

F4

edit: text or hex, encodings as in view; F2 / Ctrl+S save back to disk, F4 text / hex, F8 encoding; hex: Tab hex / characters, Ins / Del insert / remove byte

F5

copy to other panel (TR-DOS ↔ others as Hobeta)

F7

new folder (iS-DOS, FAT)

F8 / Del

delete (folders: empty ones)

F1 / Esc

close File Commander

Buttons

Files / Download Files

downloads files to host (one file as is; folders and multiple files as zip or one by one)

Files / Upload Files

uploads files from host (drop supported, files can be zipped); from zip iS-DOS and FAT keep folders, TR-DOS and CP/M take all files into one place, names cut

Disks / New Disk

empty floppy (TR-DOS, CP/M, iS-DOS), HDD (CP/M, iS-DOS, FAT16 / FAT32) or SD card image

Disks / HDD Remaster

remastering HDD image (stores zip with image and its .chs)

ext / name / size

sort of panel (right of its header): folders first; ext: by extension, then by name; size: largest first

Names

TR-DOS: 8 characters + type; CP/M and iS-DOS: 8.3; FAT: long names (NAME~1.EXT short name is added).

Split files (long file cut into parts with same name): shown as NAME.001, NAME.002…; copy joins them into one file (S3M, MOD, ZIP… by contents, otherwise BIN), except onto TR-DOS. File over 255 sectors copied or put onto TR-DOS is split same way.

Live graphs, updated twice a second. Big number is current value, line below explains it.

Z80 code at

Where Z80 runs its code: 64K address space as 4 banks of 16K (page in each bank is signed), 1K blocks glow by how often program counter is there. Big number: hottest block. Below: share of time in ROM / RAM, busy = part of frame CPU is not halted.

Host

How much of real time this browser spends emulating. Below: milliseconds per emulated frame (20 ms = real time limit).

Memory

RAM as map of 16K pages: written pages glow, pages mapped into Z80 address space now are outlined. Big number: pages written since last update.

Disk

Share of frames with floppy drive busy (reading or writing).

I/O

Z80 port accesses per frame (IN + OUT).

Frames

Emulated frames per second: 50 is real time; red above dashed line = faster than real time (Max speed, turbo).

Link to this page with parameters starts a machine as set: index.html?model=pentagon&fdd=a:trd/game.trd&run=game. Parameters may also follow #. Paths are on this site; full URL of another site works when that site allows it (CORS, e.g. raw.githubusercontent.com). What a link sets is not stored: visitor's own settings stay (only sd= switches Z-Controller on).

Parameters

rom=: one machine for everyone

1. Options / System / Custom ROM: Select ROM, machine, slots (e.g. Quick Commander in 128), Start.
2. Set clock; Options / Disk: Accurate FDD, HDD interface.
3. Save / Custom ROM: ZIP with ROM and its .json.
4. Put ZIP on this site or on GitHub, link: ?rom=rom/my_machine.zip (or rom=https://raw.githubusercontent.com/…/my_machine.zip). Other parameters (fdd=, hdd0=, run=…) work with it.

.json in ZIP

speed, fdd, hdd and ini keys win over what visitor has set in Options, while this machine runs. Order: link, then ZIP, then visitor's settings — speed= in link wins over speed of ZIP; HDD image from hdd= whose .chs has Interface= switches that interface on, over hdd of ZIP. Save / Custom ROM writes speed, fdd and hdd as machine runs now.