Latihan AOK - William Stanley

BAB 7 – William Stanley (AOK)

7.6

English :

For programmed I/O, Figure 7.5 indicates that the processor is stuck in a wait loopdoing status checking of an I/O device. To increase efficiency, the I/O software could be written so that the processor periodically checks the status of the device. If the device is not ready, the processor cam jump to other tasks.After some timed interval, The processor comes back to check status again.

       a.      Consider the above scheme for outputting data one character at a time to a printer that operates at 10 characters per second (cps). What will happen if its status is scanned every 200 ms?

      b.      Next consider a keyboard with a single character buffer. On average, characters are entered at a rate of 10 cps. However, the time interval between two consecutive key depressions can be as short as 60 ms. At what frequency should the keyboard be scanned by the I/O program?

Indonesia :

Untuk diprogram I / O , Gambar 7.5 menunjukkan bahwa prosessor terjebak dalam lingkaran menunggu loop melakukan pengecekan I / O device . Untuk meningkatkan efisiensi , I / O software bisa menjadi tertulis sehingga prosesor secara berkala memeriksa status device. Jika perangkat tidak siap , prosessor dapat melompat ke tasks lain.After beberapa waktu  interval, processor datang kembali untuk mengecek status lagi .

      a.      Pertimbangkan skema di atas untuk keluaran data satu karakter pada satu waktu ke
printer yang beroperasi pada 10 karakter per detik ( cps ) . Apa yang akan terjadi jika statusnya dipindai setiap 200 ms ?

      b.      Berikutnya mempertimbangkan keyboard dengan single character buffer. Rata-rata , karakter
dimasukkan pada tingkat 10 cps . Namun, interval waktu antara consecutive key depressions berturut-turut bisa sesingkat 60 ms . Pada frekuensi apa yang harus keyboard dipindai oleh program I/O ?

Jawab :

      a.      Terlambat 100 ms/ 5cps

      b.      Setiap 160ms

7.17

English:

A 32-bit computer has two selector channels and one multiplexor channel. Each selector channel supports two magnetic disk and two magnetic tape units. The multiplexor channel has two line printers, two card readers, and 10 VDT terminal connected to it. Assume the following transfer rates:

Disk drive 800 KBytes/s

Magnetic tape drive 200 KBytes/s

Line printer 6.6 KBytes/s

Card reader 1.2 KBytes/s

VDT 1 KBytes/s

Estimate the maximum aggregate I/O transfer rate in this system.

Indonesia :

Sebuah komputer 32-bit memiliki dua selector channels dan satu multiplexor channel. Setiap selector channel mendukung dua unit magnetic disk dan dua magnetis tape units. Saluran multiplexor memiliki dua line printers, dua Cad reader, dan 10 terminal VDT terhubung. Asumsikan kecepatan transfer berikut:

Disk drive 800 KByte / s

Magnetic tape drive yang 200 KByte / s

Line printer 6,6 KByte / s

Card reader 1.2 KByte / s

VDT 1 KByte / s

Perkirakan transfer Ade maksimum agregat I / O dalam sistem ini.

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