---
title: "Smokey"
id: 69522
type: "computer_media"
slug: "smokey"
url: "http://localhost/computer_media/smokey/"
markdown_url: "http://localhost/computer_media/smokey.md"
published_at: "2026-04-13T23:35:36+00:00"
modified_at: "2026-04-14T09:24:39+00:00"
author: "David Anderson"
featured_image:
  url: "http://localhost/wp-content/uploads/2026/04/SCR-20260413-ralq.png"
excerpt: "A DATA-driven melody player for \"On Top of Old Smokey\" with adjustable tempo, lyric display, and clever ON ERR end-of-data detection."
category:
  - name: "Archived Media"
    slug: "archived-media"
    taxonomy: "category"
    url: "http://localhost/category/archived-media/"
post_tag:
  - name: "Downloadable"
    slug: "downloadable"
    taxonomy: "post_tag"
    url: "http://localhost/tag/downloadable/"
  - name: "TS 2068"
    slug: "ts2068"
    taxonomy: "post_tag"
    url: "http://localhost/tag/ts2068/"
model:
  - name: "Timex/Sinclair 2068"
    slug: "ts-2068"
    taxonomy: "model"
    url: "http://localhost/model/ts-2068/"
indiv:
  - name: "Mark Miller"
    slug: "mark-miller"
    taxonomy: "indiv"
    url: "http://localhost/indiv/mark-miller/"
genre:
  - name: "Music"
    slug: "music"
    taxonomy: "genre"
    url: "http://localhost/type/music/"
media_type: "Program"
programmers:
  - name: "Mark Miller"
    slug: "mark-miller"
    taxonomy: "indiv"
    url: "http://localhost/indiv/mark-miller/"
download_url: "https://archive.org/download/timex-sinclair-software-archive/SMOKEY%20%28198x%29%28Miller%2C%20Mark%29%28TS2068%29%28US%29%28Program%29.zip"
mediadate: "198x"
images:
  - url: "http://localhost/wp-content/uploads/2026/04/SCR-20260413-ralq.png"
media_type_tags: "Music"
---

# Smokey

Smokey plays the melody “On Top of Old Smokey” using BEEP statements driven entirely by a DATA list encoding notes as frequency-offset and duration-value pairs. The program uses a two-byte protocol in the DATA stream: a value of 99 signals a rest (implemented via PAUSE), and a value of 100 triggers a lyric-segment display by indexing into a pre-dimensioned string array. The tempo is user-adjustable, with a base rate variable (tt) that scales all note and rest durations multiplicatively. ON ERR is used to detect the end of the DATA stream and branch to the post-playback menu, where the user can loop continuously, choose a custom tempo, or stop.

***

## Program Analysis

### Program Structure

The program divides into four logical phases:

1. **Initialization (lines 20–30):** Sets screen colors, dimensions the lyric array `a$(17,5)`, reads the song title and base rate, and sets default tempo.
2. **Display (lines 40–70):** Prints a “NOW PLAYING” banner, centered song title, and a key hint.
3. **Playback loop (lines 80–130):** Continuously reads pairs `f,v` from DATA and either plays a note, inserts a rest, or updates the lyric display. ON ERR at end-of-data redirects to cleanup.
4. **Post-play menu (lines 140–290):** Offers looping, tempo change, or stop options.

### Data Format

All musical content lives in the DATA statement at line 320 (after the song title/rate at line 310). Each note or event is encoded as a pair `f, v`:

| f value | Meaning | Action |
| --- | --- | --- |
| normal number | BEEP semitone offset | `BEEP t/v, f` — plays note at pitch `f`, duration scaled by tempo |
| 99 | Rest sentinel | `PAUSE t/v*60` — silent pause, duration scaled |
| 100 | Lyric sentinel | Prints `a$(v)` at screen position AT 5,13 with PAPER 5 |

The base duration unit `t` is calculated as `r * tt`, where `r` is read from DATA (0.08) and `tt` is the adjustable tempo multiplier (default 10), giving `t = 0.8` seconds per whole note equivalent.

### Tempo System

All durations are expressed as fractions: a quarter note is `t/4`, a dotted quarter is `t/3` (approximately), and so on. The user-adjustable `tt` variable at line 290 allows slowing down (larger values) or speeding up (smaller values) by rescaling `t` before each playback pass. The original tempo of 10 yields `t = 0.8`.

### ON ERR End-of-Data Detection

Rather than counting notes or using a sentinel that terminates the READ loop explicitly, the program uses `ON ERR GO TO 130` at line 90 to catch the “Out of DATA” error that naturally occurs when the DATA is exhausted. Line 130 then resets the error trap with `ON ERR RESET`. This is a compact idiom for infinite DATA traversal without needing to know the data length in advance.

### Lyric Array

The array `a$(17,5)` is declared but only three elements are populated at line 30: `a$(2)="c"`, `a$(4)="f"`, and `a$(16)="g7"`. These are chord or lyric fragment labels displayed on screen mid-song when the DATA stream emits a `100, v` pair. The sparse population means most of the array slots are empty strings, which would display as blanks if triggered.

### Playback Loop and RESTORE

After playback ends, line 140 calls `RESTORE 320` to rewind the DATA pointer to the note data (skipping the title/rate at line 310). If the loop flag `z$="1"` is set from a previous menu choice, the program jumps directly back to `GO TO 90`, restarting playback without re-entering the menu. This allows seamless continuous looping.

### Screen Layout

The display uses `PAPER 5` (cyan) for the banner rows at lines 0 and 21, `PAPER PI` (which evaluates to 3, magenta) with `INK 7` (white) for the key hint at line 20, and an uncolored centered title at row 10. The song title is centered using the expression `(31-LEN n$)/2` as the column argument to `AT`.

### Notable Idioms and Techniques

- `PAPER PI` uses the constant π ≈ 3.14159, which truncates to 3 (magenta) — an unusual but valid way to specify a paper color.
- `PAUSE 0: LET z$=INKEY$` at line 180 is the standard efficient keypress-wait idiom.
- `SAVE "SMOKEY" LINE 20` at line 300 saves the program with an auto-run start line, skipping the REM at line 10.
- The rest duration formula `t/v*60` converts the fractional note value into PAUSE units (50ths of a second), since PAUSE counts are in 1/50s and BEEP durations are in seconds. The factor of 60 compensates: `t/v` seconds × 50 frames/second ≈ × 60 (approximate, slightly over).

## Source Code

```
   10 REM by Mark Miller,                 Baldwin Park, CA
   20 BORDER 4: PAPER 6: CLS : DIM a$(17,5): READ n$,r
   30 LET tt=10: LET z$="": LET a$(2)="c": LET a$(4)="f": LET a$(16)="g7"
   40 PRINT PAPER 5;"********* NOW PLAYING **********"
   50 PRINT AT 10,(31-LEN n$)/2;n$
   60 PRINT PAPER 5;AT 21,0;"********* NOW PLAYING **********"
   70 PRINT PAPER PI; INK 7;AT 20,0;" TO STOP PRESS ""SHIFT"" + ""BREAK"" "
   80 LET t=r*tt
   90 READ f,v: ON ERR GO TO 130: IF f=100 THEN PRINT AT 5,13; PAPER 5;a$(v): GO TO 90
  100 IF f<>99 THEN GO TO 120
  110 PAUSE t/v*60: GO TO 90
  120 BEEP t/v,f: GO TO 90
  130 ON ERR RESET 
  140 RESTORE 320: IF z$="1" THEN GO TO 90
  150 CLS : PRINT AT 7,0;"PRESS ""1"" TO PLAY CONTINUOUSLY"
  160 PRINT '"PRESS ""2"" TO PLAY DIFFERENTLY"
  170 PRINT '"PRESS ""s"" TO STOP"
  180 PAUSE 0: LET z$=INKEY$
  190 IF z$="1" THEN CLS : GO TO 40
  200 IF z$="2" THEN GO TO 220
  210 STOP 
  220 CLS : PRINT AT 4,0;"YOU CAN PLAY THIS COMPOSITION"
  230 PRINT "AT A DIFFERENT TEMPO. THE"
  240 PRINT "ORIGINAL TEMPO IS 10. INPUT 10"
  250 PRINT "TO RETAIN THE ORIGINAL TEMPO."
  260 PRINT "INPUT A LARGER NUMBER FOR A"
  270 PRINT "SLOWER TEMPO.  INPUT A SMALLER"
  280 PRINT "NUMBER FOR A FASTER TEMPO."
  290 INPUT tt: CLS : GO TO 40
  300 SAVE "SMOKEY" LINE 20
  310 DATA "ON TOP OF OLD SMOKEY",.08
  320 DATA 0,4,100,2,0,4,4,4,7,4,100,4,12,1.33,9,.8,9,4,5,4,7,4,9,4,100,2,7,.5,0,4,0,4,4,4,7,4,100,16,7,1.33,2,.8,2,8,4,8,5,4,4,4,2,4,100,2,0,.5
```