Customarily these occupy one or more drive bays on the front of the computer case, and either interface directly with the system hardware or connect to a software data-collection system via USB.
kˌʌstəmˈɛɹᵻli ðiːz ˈɑːkjʊpˌaɪ wˈʌn ɔːɹ mˈoːɹ dɹˈaɪv bˈeɪz ɔnðə fɹˈʌnt ʌvðə kəmpjˈuːɾɚ kˈeɪs, ænd ˈiːðɚɹ ˈɪntɚfˌeɪs dᵻɹˈɛktli wɪððə sˈɪstəm hˈɑːɹdwɛɹ ɔːɹ kənˈɛkt tʊ ɐ sˈɔftwɛɹ dˈeɪɾəkəlˈɛkʃən sˈɪstəm vˈaɪə jˌuːˌɛsbˈiː.