Friden Flexowriter
The writing machine or paper tape writing machine is an electrical or electro-mechanical tools for word processing.
The first writing machine appear in the 1950s and were further developed in the following years to complex text processing systems.
Tape write machine
Parts of the machine were an electric typewriter, a paper tape puncher and paper tape reader, one or two, which were coupled to each other by a logic circuit composed of transistors or relays.
The operator of the supplying of the typewriter actions were detected with electro-mechanical, electronic or optical contacts and binary-coded via the logic circuit on a paper tape. Conversely, the tape data could be transformed via a paper tape reader into control signals for the automatic control of the typewriter. The mechanical elements of the typewriter were driven over this electromagnets.
An example of such a system is the Friden Flexowriter. This even allowed to work with two perforated strips. In this way, for example, could be combined with a pre-fabricated letter with a recipient address (so-called mail merge ). This form letters themselves could create individually without having to type each letter.
Paper tape
The productive use paper tape controlled machine was made up in the 1980s, as the tape technology with seven or eight holes ( without sprocket holes ) advantages offered by column. It has often been resorted to descendants of the ASCII character set because of the compatibility with IBM.
Control character
The control characters used on the punched tape to control writing machines are based on the ASCII character set used today, which has its origin in the automated output of text on word processor and telex machines and their storage and transmission. The first 32 characters of the sentence define control characters which perform certain actions on the issuing machine and control the communication with a remote site. To be limited to the issue, are examples of ASCII control characters ( complete list see there) " BEL " (= " bell", Acoustic signal, usually a bell), "LF" ( = " line feed", line feed) " CR" ( = "carriage return", carriage return ), " HT " (= " horizontal tab " tab) and "FF " (= " form feed ", feed) called.
Correction
The output on the tape puncher made immediately in writing. This coded character to output the binary in the form of mostly 7 holes per row. A perforation presented that the bit is represents the correction of a once as " perforated " character was possible by subsequently every seven bits have been drilled on the position of the incorrect character at a time. Once in a paper tape punched holes could not be easily replenished. A series of seven bits set was ignored by the issuing machine. & b1111111 ( = 127 or 7F ) represents the ASCII control character " DEL " (= " deleted", deleted) dar. It could so arbitrarily many consecutive characters are deleted.
Text modules
Paper tape offered the opportunity to work with text blocks. For this to be used punched tape were either the respective tape sections simply glued together or sequentially inserted into a reader and punched to the desired location.
Duplication
Tape could be duplicate. For this purpose, the source tape is loaded and processed by the machine. In the same step, then all actions, whether automated imported or entered manually, reissued on a new tape. The new tape quasi then contained a corrected version, since corrections and Stop commands are not automatically issued with the new tape.
Letters
For the automated creating form letters two reading stations were needed. In the first reading station of the tape is loaded with the address data ( including individual variable addressing and data), in the second of glued together to form a ring form letter. Control codes in two strips regulated the switching between the two reading stations.
If the machine fed with endless paper so rattled this until either the address or the paper ran out. In the first case, the process was complete, in the second case had to take the next box of paper the operator.