Autosave: 2024-09-20 08:00:03

zk/1726814727_LUWV.md

@@ -0,0 +1 @@
+# Turing Mach

zk/Delay_line_memory.md

@@ -17,6 +17,24 @@ created: Wednesday, September 18, 2024
 - It worked as follows:
   - Imagine we have an 8-bit number. The number is input as a sequence of pulses
     where a pulse is 1 and the absence of a pulse is 0.
-  - The pulses are converted into sound waves (as with a speaker) and sent
+  - The pulses are converted into sound waves (using a transducer, as with a
-    through a mercury-filled tube.
+    speaker) and sent through a mercury-filled tube.
-  - The length of the tube is calculated...
+  - The length of the tube is calculated so that it takes exactly the time of
+    one machine cycle for a pulse to travel from one end to the other
+  - At the other end of the tube, another transducer converts the sound waves
+    back to electrical pulses
+  - This operates in a loop: the pulses go back into the input end of the tube
+    and the cycle runs again.
+
+To read the data, the computer would "listen" to the pulses coming out of the
+receiving end. To write new data, the computer would inject new pulses at the
+precise moment when it wants to change a '0' to a '1' or vice versa.
+
+For an 8-bit number there would be 8 pulses for each bit and it would be
+necessary to keep track of 8 specific positions in the delay line where each bit
+would be stored.
+
+The limitations were timing - difficult to keep track of each precise bit and
+when it would arrive at the output. Also it was sequential rather than random
+access. Not every bit could be accessed at once, you had to wait for its time
+slot to come around to access it.

zk/The_History_of_Computing_Swade.md

@@ -370,8 +370,8 @@ the ABC to make ENIAC.
 ### Post-EDVAC devices
 
 There were several notable devices which attempted to implement the architecture
-described in the _First Draft_ using vacuum tubes and other fully-electronic
+described in the _First Draft_ using vacuum tubes for logic operations and a
-methods for memory:
+variety of different electronic methods for memory:
 
 - the Manchester "Baby"
 - the Cambridge EDSAC
@@ -379,6 +379,8 @@ methods for memory:
 
 #### Manchester Baby (1948)
 
+![The Manchester Baby Computer](../img/manchester_baby.png)
+
 - An experimental computer intended to create the
   [von Neumann architecture](CPU_architecture.md) using
   [Williams_Tube_RAM](Williams_Tube_RAM.md)
@@ -390,15 +392,17 @@ methods for memory:
 
 #### EDSAC (1949) J.Wilkes et al.
 
+![EDSAC](../img/EDSAC.jpg)
+
 - _Electronic Delay Storge Automatic Computer_
 
-- Constructed by Maurice Wilkes and others at the Mathematical Laboratory
+- Constructed by Maurice Wilkes and others at the Mathematical Laboratory of the
-  Cambridge University.
+  University of Cambridge.
 
 - The second digital stored-program computer after the Manchester Baby.
 
 - It used vacuum-tubes for the arithmetical operations in the ALU and mercury
-  delay lines for the RAM.
+  [delay line memory](Delay_line_memory.md) for the RAM.
 
 - Designed to be used by relatively non-specialist practitioners from other
   university departments who were expected to program it themselves. To this
@@ -410,6 +414,27 @@ methods for memory:
     operations)
   - diagnostics: techniques for verifying program code and its correctness
 
+![Programming Digital Electronic Computer book](../img/programming_a_digital_electronic_computter.jpg)
+
 - The key players wrote the first textbook on programming in 1951: _The
   Preparation of Programs for an Electronic Digital Computer_ (Wilkes, Wheeler,
   and Gill)
+
+#### The Automatic Computing Engine (ACE) (1946) Alan Turing
+
+- Technical design provided by Alan #Turing working at the Mathematics Division
+  of the National Physical Laboratory. The product of Turing's theoretical work
+  in "On Computable Numbers" where he proposes the concept of a
+  [Turing_machine](Turing_machines.md) and based on his experience with early
+  single-purpose computing devices at Bletchley.
+
+- Due to secrecy over wartime work, it was hard for get Turing to build a fully
+  electronic implementation since this would disclose advances made during the
+  War. Tommy Flowers was intended to be brought in to build it but again this
+  was scuppered over the classification of wartime technology. Had this not been
+  the case, it is likely it would've been seen as on par with the EDVAC in its
+  design, if not dwarfing it.
+
+- Turing proposed a stored program architecture with high-speed memory. It would
+  be more perfomant than the EDVAC as a result. It used punched cards for the
+  input of data and programs