diff --git a/emulator.pas b/emulator.pas
index b2df9c3..652353d 100644
--- a/emulator.pas
+++ b/emulator.pas
@@ -31,20 +31,31 @@ const
     {$endif}
 
 var
-    Hlt, Echo: boolean; //Halt and echo flags
+    Hlt, Echo{$ifdef floppy}, DiscRead, DiscWrite, DiscTrackSet, DiscSectSet{$endif}: boolean; //Halt and echo flags and disc system flags
     Op, Regs: 0 .. $f; //Opcode
     X, Y: 0 .. 3; //Register arguments
     Addr, IP, RP: word; //Immediate or address argument and instruction and return pointers
     R: array [0 .. 3] of byte; //General-purpose registers
     Mem: array [0 .. LastRAM] of byte; //Random access memory
-    Prog{$ifdef printer}, Prn{$endif}{$ifdef tape}, TapeIn, TapeOut{$endif}: file of byte; //Program file, line printer, and tape reader and punch tapes
+    {$ifdef floppy}
+    DiscSB: array [0 .. $88] of byte; //Sector buffer for the disc system
+    DiscSBP: 0 .. $88; //Sector buffer pointer
+    {$endif}
+    Prog{$ifdef printer}, Prn{$endif}{$ifdef tape}, TapeIn, TapeOut{$endif}{$ifdef floppy}, Disc{$endif}: file of byte; //Program file, line printer, tape reader and punch tapes, and current disc
     {$ifdef tape}
     Reader, Punch: Tape; //States of the tape reader and punch
     Tapes: file of Tape; //File storing the states of the tape reader and punch
     {$endif}
+    {$ifdef floppy}
+    Disc0Path, Disc1Path, DiscPath: shortstring; //Paths of the discs in the drives and the current disc
+    Discs: file of shortstring; //File storing the state of the disc system
+    {$endif}
     Ch, Scan: ansichar; //Character for input and output and scancode for non-ASCII keys
     Verbose, IC, LFX: integer; //Verbose flag, instruction counter for CPU speed, and line feed position marker
-    Fetched: byte; //Fetched byte
+    Fetched{$ifdef floppy}, Disc0Track, Disc1Track, Disc0Sect, Disc1Sect{$endif}: byte; //Fetched byte, and disc drive locations
+    {$ifdef floppy}
+    DiscDrive: 0 .. 1; //Current disc drive number
+    {$endif}
 
 //Terminal output
 procedure Output;
@@ -68,9 +79,9 @@ end;
 
 {$ifndef fast}
 //Wait to emulate CPU speed of roughly 500 KIPS
-procedure wait;
+procedure wait (I: integer);
 begin
-    if IC div 500 = 0 then sleep (1)
+    if IC div 500 < I then sleep (I)
     else begin
         sleep (IC div 500);
         if IC mod 500 >= 250 then sleep (1);
@@ -87,7 +98,7 @@ begin
     //Terminal input
     if W = $ffff then begin
         {$ifndef fast}
-        wait;
+        wait (1);
         {$endif}
         //Read a keypress
         Ch := ReadKey;
@@ -116,8 +127,7 @@ begin
     //Tape reader
     else if W = $fffd then begin
         {$ifndef fast}
-        wait;
-        sleep (1);
+        wait (2);
         {$endif}
         assign (Tapes, ExpandFileName ('~/.thingamajig/tapes'));
         //Check the reader state
@@ -153,6 +163,21 @@ begin
         end;
     end
     {$endif}
+    {$ifdef floppy}
+    //Floppy disc drive system
+    //Data
+    else if W = $fffc then begin
+        if DiscRead then begin
+            B := DiscSB [DiscSBP];
+            if DiscSBP < $88 then DiscSBP := DiscSBP + 1
+            else begin
+                DiscSBP := 0;
+                DiscRead := false;
+            end;
+        end
+        else B := 0;
+    end
+    {$endif}
     //Unused addresses
     else if W > LastRAM then B := 0
     //Regular load
@@ -166,7 +191,7 @@ begin
     //Terminal output
     if W = $ffff then begin
         {$ifndef fast}
-        wait;
+        wait (1);
         {$endif}
         Ch := ansichar (B);
         Output;
@@ -176,6 +201,9 @@ begin
     {$ifdef printer}
     //Printer
     else if W = $fffe then begin
+        {$ifndef fast}
+        wait (1);
+        {$endif}
         assign (Prn, '/dev/usb/lp0');
         try
             rewrite (Prn);
@@ -189,8 +217,7 @@ begin
     //Tape punch
     else if W = $fffd then begin
         {$ifndef fast}
-        wait;
-        sleep (19);
+        wait (20);
         {$endif}
         assign (Tapes, ExpandFileName ('~/.thingamajig/tapes'));
         //Check the punch state
@@ -246,6 +273,172 @@ begin
         end;
     end
     {$endif}
+    {$ifdef floppy}
+    //Floppy disc drive system
+    //Data
+    else if W = $fffc then begin
+        if DiscWrite then begin
+            DiscSB [DiscSBP] := B;
+            if DiscSBP < $88 then DiscSBP := DiscSBP + 1
+            else begin
+                DiscSBP := 0;
+                DiscWrite := false;
+            end;
+        end
+        else if DiscTrackSet then begin
+            if B <= $4c then begin
+                if DiscDrive = 0 then begin
+                    {$ifndef fast}
+                    if Disc0Track > B then wait (((Disc0Track - B) * 10) + 45 )
+                    else if B > Disc0Track then wait (((B - Disc0Track) * 10) + 45 );
+                    {$endif}
+                    Disc0Track := B;
+                end
+                else begin
+                    {$ifndef fast}
+                    if Disc1Track > B then wait (((Disc1Track - B) * 10) + 45 )
+                    else if B > Disc1Track then wait (((B - Disc1Track) * 10) + 45 );
+                    {$endif}
+                    Disc1Track := B;
+                end;
+            end;
+            DiscTrackSet := false;
+        end
+        else if DiscSectSet then begin
+            if B <= $1f then begin
+                if DiscDrive = 0 then Disc0Sect := B
+                else Disc1Sect := B;
+            end;
+            DiscSectSet := false;
+        end;
+    end
+    //Command
+    else if W = $fffb then begin
+        B := B and $f;
+        //Reset the system
+        if B and $c = 0 then begin
+            Disc0Track := 0;
+            Disc1Track := 0;
+            Disc0Sect := 0;
+            Disc1Sect := 0;
+            DiscRead := false;
+            DiscWrite := false;
+            DiscTrackSet := false;
+            DiscSectSet := false;
+            for DiscSBP := 0 to $88 do DiscSB [DiscSBP] := 0;
+            DiscSBP := 0;
+        end
+        //Read a sector from the buffer to the computer
+        else if B and $e = 4 then begin
+            if DiscWrite = false then if DiscTrackSet = false then if DiscSectSet = false then begin
+                DiscRead := true;
+                DiscSBP := 0;
+            end;
+        end
+        //Write a sector from the computer to the buffer
+        else if B and $e = 6 then begin
+            if DiscRead = false then if DiscTrackSet = false then if DiscSectSet = false then begin
+                DiscWrite := true;
+                for DiscSBP := 0 to $88 do DiscSB [DiscSBP] := 0;
+                DiscSBP := 0;
+            end;
+        end
+        //Set the track to be accessed
+        else if B and $e = 8 then begin
+            if DiscRead = false then if DiscWrite = false then if DiscSectSet = false then begin
+                DiscDrive := B and 1;
+                DiscTrackSet := true;
+            end;
+        end
+        //Set the sector to be accessed
+        else if B and $e = $a then begin
+            if DiscRead = false then if DiscWrite = false then if DiscTrackSet = false then begin
+                DiscDrive := B and 1;
+                DiscSectSet := true;
+            end;
+        end
+        //Read a sector from the disc to the buffer
+        else if B and $e = $c then begin
+            if DiscRead = false then if DiscWrite = false then if DiscTrackSet = false then if DiscSectSet = false then begin
+                {$ifndef fast}
+                wait (5);
+                {$endif}
+                assign (Discs, ExpandFileName ('~/.thingamajig/discs'));
+                //Check the system state
+                if FileExists (ExpandFileName ('~/.thingamajig/discs')) then begin
+                    try
+                        reset (Discs);
+                        read (Discs, Disc0Path);
+                        read (Discs, Disc1Path);
+                        close (Discs);
+                    except
+                    end;
+                end;
+                //Set the drive
+                if B and 1 = 0 then DiscPath := Disc0Path
+                else DiscPath := Disc1Path;
+                assign (Disc, DiscPath);
+                //Read
+                try
+                    reset (Disc);
+                    if FileSize (Disc) = $526a0 then begin
+                        for DiscSBP := 0 to $88 do begin
+                            if B and 1 = 0 then seek (Disc, (Disc0Track * $1120) + (Disc0Sect * $89) + DiscSBP)
+                            else seek (Disc, (Disc1Track * $1120) + (Disc1Sect * $89) + DiscSBP);
+                            read (Disc, DiscSB [DiscSBP]);
+                        end;
+                        close (Disc)
+                    end
+                    else begin
+                        close (Disc);
+                        for DiscSBP := 0 to $88 do DiscSB [DiscSBP] := 0;
+                    end;
+                except
+                    for DiscSBP := 0 to $88 do DiscSB [DiscSBP] := 0;
+                end;
+            end;
+        end
+        //Write a sector from the buffer to the disc
+        else if B and $e = $e then begin
+            if DiscRead = false then if DiscWrite = false then if DiscTrackSet = false then if DiscSectSet = false then begin
+                {$ifndef fast}
+                wait (5);
+                {$endif}
+                assign (Discs, ExpandFileName ('~/.thingamajig/discs'));
+                //Check the system state
+                if FileExists (ExpandFileName ('~/.thingamajig/discs')) then begin
+                    try
+                        reset (Discs);
+                        read (Discs, Disc0Path);
+                        read (Discs, Disc1Path);
+                        close (Discs);
+                    except
+                    end;
+                end;
+                //Set the drive
+                if B and 1 = 0 then DiscPath := Disc0Path
+                else DiscPath := Disc1Path;
+                if DiscPath <> '' then begin
+                    assign (Disc, DiscPath);
+                    //Write
+                    try
+                        reset (Disc);
+                        if FileSize (Disc) = $526a0 then begin
+                            for DiscSBP := 0 to $88 do begin
+                                if B and 1 = 0 then seek (Disc, (Disc0Track * $1120) + (Disc0Sect * $89) + DiscSBP)
+                                else seek (Disc, (Disc1Track * $1120) + (Disc1Sect * $89) + DiscSBP);
+                                write (Disc, DiscSB [DiscSBP]);
+                            end;
+                            close (Disc);
+                        end
+                        else close (Disc);
+                    except
+                    end;
+                end;
+            end;
+        end;
+    end
+    {$endif}
     //Regular store
     else if W <= LastRAM then Mem [W] := B;
 end;
@@ -281,6 +474,21 @@ begin
     Punch.Pos := 0;
     {$endif}
 
+    {$ifdef floppy}
+    //Initialise the disc system
+    Disc0Path := '';
+    Disc1Path := '';
+    DiscRead := false;
+    DiscWrite := false;
+    DiscTrackSet := false;
+    DiscSectSet := false;
+    DiscSBP := 0;
+    Disc0Track := 0;
+    Disc1Track := 0;
+    Disc0Sect := 0;
+    Disc1Sect := 0;
+    {$endif}
+
     //Check the arguments
     if ParamCount = 0 then begin
         writeln ('Usage: emulator (-v) program (2> verbose_output)');
@@ -443,7 +651,7 @@ begin
     end;
 
     {$ifndef fast}
-    wait;
+    wait (1);
     {$endif}
 
 end.
diff --git a/floppyctl.pas b/floppyctl.pas
new file mode 100644
index 0000000..3a99785
--- /dev/null
+++ b/floppyctl.pas
@@ -0,0 +1,73 @@
+program FloppyCtl;
+
+{$MODE OBJFPC}
+
+uses SysUtils;
+
+var
+    Disc0, Disc1: shortstring; //States of the floppy discs
+    State: file of shortstring; //File storing the states of the floppy discs
+    Set0, Set1: integer; //Whether to (re)set the discs
+
+begin
+
+    //Check the arguments
+    if ParamCount > 4 then begin
+        writeln ('Usage: floppyctl (-0 disc) (-1 disc)');
+        halt (1);
+    end
+    else if ParamCount mod 2 <> 0 then begin
+        writeln ('Usage: floppyctl (-0 disc) (-1 disc)');
+        halt (1);
+    end;
+    if ParamStr (1) = '-0' then begin
+        Set0 := 2;
+        Set1 := 0;
+        if ParamStr (3) = '-1' then begin
+            Set1 := 4;
+        end;
+    end
+    else if ParamStr (1) = '-1' then begin
+        Set0 := 0;
+        Set1 := 2;
+        if ParamStr (3) = '-0' then Set0 := 4;
+    end
+    else begin
+        writeln ('Usage: floppyctl (-0 disc) (-1 disc)');
+        halt (1);
+    end;
+
+    //Assign the state file
+    assign (State, ExpandFileName ('~/.thingamajig/discs'));
+
+    //Read existing state if any
+    if FileExists (ExpandFileName ('~/.thingamajig/discs')) then begin
+        try
+            reset (State);
+            read (State, Disc0);
+            read (State, Disc1);
+            close (State);
+        except
+        end;
+    end
+    //Or else assign a default state
+    else begin
+        Disc0 := '';
+        Disc1 := '';
+    end;
+
+    //Get the files
+    if Set0 <> 0 then Disc0 := ExpandFileName (ParamStr (Set0));
+    if Set1 <> 0 then Disc1 := ExpandFileName (ParamStr (Set1));
+
+    //Write the state
+    try
+        rewrite (State);
+        write (State, Disc0);
+        write (State, Disc1);
+        close (State);
+    except
+        writeln ('Error: could not set the disc(s)');
+    end;
+
+end.
diff --git a/readme.md b/readme.md
index 48bcd8b..0edb0ea 100644
--- a/readme.md
+++ b/readme.md
@@ -8,11 +8,10 @@ https://ahti.space/git/crazyettin/Thingamajig.
 Included Software
 -----------------
 
-The repository includes an emulator implementation of Thingamajig with a
-control program for the emulated paper tape reader and punch, and an
-assembler and a disassembler, all written in FreePascal. It also
-includes couple of simple example programs for Thingamajig written in
-assembly.
+The repository includes an emulator implementation of Thingamajig with
+storage device control programs, and an assembler and a disassembler,
+all written in FreePascal. It also includes couple of simple example
+programs for Thingamajig written in assembly.
 
 Registers and Memory
 --------------------
@@ -92,12 +91,13 @@ implementation has a front panel the IPL is optional. The instruction
 and return pointers are initialised as 0 and the first address after RAM
 respectively, while other registers and RAM are uninitialised.
 
-Emulator and Tapectl
---------------------
+Emulator and Storage Device Control Programs
+--------------------------------------------
 
 Usage:
   * emulator (-v) program (2> verbose_output)
   * tapectl (-r tape) (-p tape)
+  * floppyctl (-0 disc) (-1 disc)
 
 By default the emulator runs at roughly 500 KIPS and has 2 KiB of RAM.
 The arguments -dRAM4, -dRAM8, -dRAM16, -dRAM32, and -dRAM64 can be used
@@ -117,12 +117,36 @@ standard uses. The backspace and delete keys input their respective
 characters and non-character keys null.
 
 In Linux the emulator can be compiled with support for a character
-printer and an emulated high speed (roughly 500 CPS in and 50 CPS out)
-8-bit paper tape reader and punch with the arguments -dprinter and
--dtape respectively. The printer is mapped to address FFFE and the tape
-reader and punch to FFFD. The printer prints into /dev/usb/lp0 and the
-tape files read from and punched to are (re)set using the program
-tapectl with the arguments -r and -p respectively.
+printer, an emulated high speed (roughly 500 CPS in and 50 CPS out)
+8-bit paper tape reader and punch, and an emulated two-drive 8" floppy
+disc system with the arguments -dprinter, -dtape, and -dfloppy
+respectively. The printer is mapped to address FFFE, the tape reader and
+punch to FFFD, and the disc system to FFFB and FFFC. The printer prints
+into /dev/usb/lp0. The tape files read from and punched to are (re)set
+using the program tapectl with the arguments -r and -p respectively and
+the disc files in drives 0 and 1 using the program floppyctl with the
+arguments -0 and -1 respectively. The disc system uses single-sided
+discs with 77 tracks of 32 sectors of 137 bytes, or 337568 bytes in
+total: the disc files must be of this size.
+
+The floppy disc system uses two ports: command at FFFB and data at FFFC.
+Only the low nibble of the command port is used, consisting of a
+three-bit command followed by a one-bit drive number used as an argument
+by instructions 4-7. The track or sector to be accessed is input to and
+the buffer accessed sequentially through the data port after the
+relevant command is input to the command port. New commands other than
+resetting the system are ignored until the current command is fully
+executed.
+
+The commands for the disc system are:
+ 0: Reset the system.
+ 1: "
+ 2: Read a sector from the buffer to the computer.
+ 3: Write a sector from the computer to the buffer.
+ 4: Set the track to be accessed.
+ 5: Set the sector to be accessed.
+ 6: Read a sector from the disc to the buffer.
+ 7: Write a sector from the buffer to the disc.
 
 The IPL loads the program specified as an argument when running the
 emulator.