GNU/Linux Desktop Survival Guide by Graham Williams
Desktop Survival Project Home Preface Advocacy History Distributions Installing GNU/Linux Basic Survival Wajig Applications AI, Machine Learning, Data Science Android - GNU/Linux Devices Audio Backup Booting CD Chinese ChRoot Clock Command Line Databases DIA Directories Disks EcoSysL Emacs Email Evolution Files File Systems Firewalls Floppy Disks FreedomBox Glade GNOME Graphics, Images, Photos Hardware Initialisations on Booting Installation Examples Internet IOT Java KDE Kernels Keyboard Konqueror KVM Switch LATEX Log System Login Magellan MATE Mathematics Memory Modems Mounting Devices MS/Windows Music MySQL Nautilus Networks Nextcloud Network File System NFS NT File System Oracle Packages Partitions Passwords PDF Power Management PPP Presentations Printing Python R Remote Desktops Rsync Samba Scanning Science Screens Security Spreadsheet SSH Swap Teradata Data Warehouse Themes TV Unity USB Version Control Video Virtualization Voice over IP WebCam WordPress Web Sites Word Processing and Printing X XML Troubleshooting Index

CLICK HERE TO VISIT THE UPDATED SURVIVAL GUIDE

Copy a Floppy

The common geometry of a 3.5" floppy disk has 18 sectors per track with two heads and 80 cylinders. Thus, optimising the dd command to read the contents of a floppy we would use:

  $  dd bs=2x80x18b if=/dev/fd0 of=/tmp/floppy.image
  1+0 records in
  1+0 records out

Then to write to another floppy:

  $  dd bs=2x80x18b < /tmp/floppy.image > /dev/fd0 
  1+0 records in
  1+0 records out

The 2x multiplies the sector size by the number of heads while the 80x identifies the number of cylinders. The 18b specifies 18 sectors of 512 bytes. This gives a total of 1,474,560 bytes and issues a single 1,474,560-byte read request to /dev/fd0 and a single 1,474,560 write request to /tmp/floppy.image, rather than the corresponding cp command:

  $ cp /dev/fd0 /tmp/floppy.image

which issues 360 reads and writes of 4,096 bytes each.