projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 2c2d3e6c TL |
1 | .TH PC 4 |
| 2 | .SH NAME | |
| 3 | pc \- PC-11 paper tape reader/punch | |
| 4 | .SH DESCRIPTION | |
| 5 | .I Ppt | |
| 6 | refers to the PC-11 paper tape reader or punch, | |
| 7 | depending on whether it is read or written. | |
| 8 | .PP | |
| 9 | When | |
| 10 | .I ppt | |
| 11 | is opened for writing, a 100-character leader | |
| 12 | is punched. | |
| 13 | Thereafter each byte written is punched on | |
| 14 | the tape. No editing of the characters | |
| 15 | is performed. | |
| 16 | When the file is closed, a 100-character trailer is punched. | |
| 17 | .PP | |
| 18 | When | |
| 19 | .I ppt | |
| 20 | is opened for reading, the process | |
| 21 | waits until tape is placed in the reader and the reader | |
| 22 | is on-line. | |
| 23 | Then requests to read cause the characters read | |
| 24 | to be passed back to the program, again without | |
| 25 | any editing. | |
| 26 | This means that several null leader characters | |
| 27 | will usually appear at the beginning of the file. | |
| 28 | Likewise several nulls are likely to appear at the end. | |
| 29 | End-of-file is generated when the tape runs out. | |
| 30 | .PP | |
| 31 | Seek calls for this file are meaningless. | |
| 32 | .SH FILES | |
| 33 | /dev/ppt | |
| 34 | .SH BUGS | |
| 35 | If both the reader and the punch are open simultaneously, | |
| 36 | the trailer is sometimes not punched. | |
| 37 | Sometimes the reader goes into a dead state in which it cannot be | |
| 38 | opened. |