By using a simple write strategy we have found that a wide range of li
near velocities can be covered for direct overwrite in high-density ph
ase-change recording. This is especially advantageous for data recordi
ng where the application of constant angular velocity facilitates fast
seek and short random-access times. In the case of repeated overwriti
ng, material flow will limit the number of cycles, particularly if a f
ixed pseudo-random data pattern is used: We studied how a random bit s
hift can reduce this problem and found that a relatively large shift o
f up to 100 bytes was required. Using these techniques in an optimized
disc structure we achieved more than 100,000 overwrite cycles on a 2.
6 Gbyte 12 cm phase-change disc.