#1343 Slow CD-ROM emulation since r12116

[reet]

Hi,

We are booting an ISO of size 9.2M with bochs:

ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
ata0-master: type=cdrom, path=bootable.iso, status=inserted
boot: cdrom

Since revision r12116 Bochs needs ~20 seconds to load the image (on an Intel(R) Xeon(R) CPU E31230 @ 3.20GHz machine). r12115 needs less than 1 second for the same image.

Kind regards,
- reto

[Volker Ruppert]

It's not a bug, it's a feature: the seek latency of the CD-ROM drive. In previous versions the data was available immediately after sending the command. Now there is a latency to make the drives behave more like real hardware. The first version has used a fixed value of 80 msec after sending the command for the CD-ROM. Today I have improved this feature and make the time depend on the distance between previous and new block address. Now the maximum value should only occur at the first access or after media change. Please let us know when reading from CD with Bochs is still slower than real hardware.

[reet]

On 02/09/2014 09:49 PM, Volker Ruppert wrote:

It's not a bug, it's a feature: the seek latency of the CD-ROM drive. In previous versions the data was available immediately after sending the command. Now there is a latency to make the drives behave more like real hardware. The first version has used a fixed value of 80 msec after sending the command for the CD-ROM. Today I have improved this feature and make the time depend on the distance between previous and new block address. Now the maximum value should only occur at the first access or after media change. Please let us know when reading from CD with Bochs is still slower than real hardware.

Ok thanks for the clarifications and the improvements in the code. The
speed of the CD-ROM drastically increased again and it "feels" like before.

Thanks!
- reto