Solid-state disks use arrays of flash-memory chips for data storage. They adopt multichannel architectures to exploit parallelism among flash operations. Under real disk workloads, a channel spends nearly the same amount of time on writing host data and collecting garbage. Thus, the key to the success of multichannel architectures is to achieve high parallelism among channel operations under these two kinds of activities. This study presents a channel management scheme that comprises a write-buffer design and two channel management policies. The proposed scheme is designed to be generic, and it is applicable to both hybrid mapping and page-level mapping. Our experimental results show that the proposed management scheme doubles the average number of write requests completed per second (e.g., write IOPS) of a baseline multichannel architecture. We also successfully implemented the proposed scheme in a real solid-state disk and demonstrated the feasibility of our approach.